U and Z Type Flat Plate Heat Exchanger

The heat exchanger is a simple mechanical device that is used to transfer heat between two fluids. Its only function is to facilitate the transfer of heat from the hot fluid to cold fluid and its design is made to maximize the transfer of heat. Base on the working mechanism of the heat exchanger there are two main types, one is a direct heat exchanger where the hot and cold fluid is in direct contact with each other, and the second is an indirect heat exchanger which hot and cold fluids are in separate channels. In the indirect types of heat exchangers, different types of design can transfer heat between fluids. These designs include

Tube in Tube Type Heat Exchanger

This type of heat exchanger transfers heat between the fluid using two tubes of different diameters. One tube with a smaller diameter with respect to the other tube is placed inside the larger tube and then fluids with different temperatures are allowed to flow in different tubes. Heat exchange between hot and cold fluid happens at the interface of the inner tube.

Shell and tube type Heat Exchanger

This type of heat exchanger transfers heat between fluids using more than one tube and a shell. Two or more tubes are placed parallel to each other inside a shell where hot fluid usually flows inside the shell and cold flow inside tubes. The temperature difference between the fluids across the tube thickness allows the transfer of heat from the hot fluid to the cold fluid. 

Plate Type Heat Exchanger

This type of heat exchanger transfer heat between fluid using a series of simple flat plates which are connected using gaskets. The spacing between the plates provides a channel for the flow of fluid where the two consecutive channels contain two different fluids. In this manner, each plate of heat exchanger has two different fluids on its different plates. 

Plate Heat Exchanger

The flat plate heat exchanger was designed and developed in 1920 using a number of plates in such a manner that each set of plates has some space in which it contains a liquid or gas matter for heat transfer. Two adjacent sets of places have two different fluid for heat transfer from which one fluid has a higher temperature than the other. Fluid usually enters and leaves perpendicular to the plate of heat exchanger using the holes provided at the end of plates. Movement of one fluid between different sets of plates is made possible by connecting every third set with the first one using pipes as shown in the figure below. In this manner, every set which contains hot fluid is surrounded by the cold fluid and every cold fluid set is surrounded by hot fluid (shah, 2003).

 

Based on the assembly of the plates there are two main types of flat plate heat exchangers. In the first type, the plate is attached to each other using simple nut and bolts where the gap between plate and joints is made fluid-tight by placing gasket. This type of heat exchanger can resist temperature up to 200 C and can hold the pressure of 25 bars.  In second type plates are simply brazed together where extended edges of plates provide gap required between plates for fluid flow. This type can work with a high temperature of up to 1100 C and can resist even high pressure (Bari, 2015). This type has a more compact design and is lightweight as compared to the first type. The material used for plates is stainless steel in most cases due to its high strength, corrosion resistance, and good thermal conductivity. In some cases, aluminum and copper can also be used. 

Working of the flat plate heat exchanger

Flat plate heat exchanger working follows the basic principle of thermodynamics and heat transfer that say that heat transfer from the region of higher potential to the region of lower potential by methods of conduction and convection. In a flat plate heat exchanger, the hot fluid present in a set of plates tries to transfer its heat to its side of the plate surface through convection. The heat from one side of a plate is transferred to its other side using conduction and from that opposite side of the plate, the heat is transferred to cold fluid using convection. The amount of heat transfer between hot and cold fluid depends on the overall heat transfer coefficient of the flat plate heat exchanger (shah, 2003). 

 

Types of Flat Plate Heat Exchanger

Base on the direction of flow of high and low-temperature fluid moving inside the channels of the flat plate heat exchanger is divided into 5 different classes which include U type, Z type, and Concurrent flow and Counter Concurrent flow.

U type flow  Heat Exchanger

U type flow in flat plate heat exchanger is one in which the flow of cold and hot fluid is in the form of the English alphabet U. This U shape flow starts from the inlet and ends at the outlet of the flat plate heat exchanger. This type of flow enables fluid to spend more time inside the channel of the flat plate heat exchanger which in return enables greater heat to absorb from hot to the cold fluid. This type of flow has one disadvantage and that is it has greater pressure drop due to difficulty in the fluid flow which reduces the overall performance of the system.

Z type of flow flat plate Heat Exchanger

Z type flow in flat plate heat exchanger is one in which the flow of cold and hot fluid is in the form of the English alphabet Z. This U shape flow starts from the inlet and ends at the outlet of the flat plate heat exchanger making the shape similar to Z. This type of flow enables fluid to move smoothly with a greater time of flow inside the channel of the flat plate heat exchanger which in return enables greater heat to absorb from hot to the cold fluid. This type of flow has one disadvantage and that is it has greater pressure drop due to difficulty in the fluid flow which reduces the overall performance of the system but is still better than U type flow.

Concurrent flow flat plate Heat Exchanger

The concurrent flow of fluid inside the flat plate heat exchanger is one in which the direction of motion of hot fluid and cold fluid moving inside the flat plate heat exchanger is concurrent with each other. The temperature profile in this type of flow shows that the temperature of hot fluid and cold fluid decreases and increases in a very similar manner. Both fluid exist heat exchangers at the temperature very close to each other.

Counter Concurrent flow flat plate Heat Exchanger

Counter Concurrent flow hot and cold fluid inside the channels of the flat plate heat exchanger is one in which the direction of motion of cold and hot fluid inside the flat plate heat exchanger is opposite to each other. The temperature profile in this type of flow shows that the temperature of hot fluid and cold fluid decreases and increases keeping the temperature difference constant. Both fluids exist heat exchangers at the temperature very different from each other.

Mode of heat transfer in the flat plate heat exchanger

Heat Transfer between fluid, solids and between fluid and solid happens because of any of the below mention two methods. That is conduction and convection mode of heat transfer. Both mode required medium to transfer heat from area of high temperature to area of low temperature.

Conduction in the flat plate Heat Exchanger

Transfer of heat from region of high temperature to the region of low temperature in a solid object body happen due to process of conduction. It depends on the solid body ability to transfer temperature and the total temperature difference between the high and low temperature areas (Bari, 2015). It can be calculated as

Q=k*A*∆T

Here

Q represents the heat transferred

k represents the material thermal conductance 

A represents the plate cross section area 

∆Trepresents the  temperature difference  

Convection in the flat plate Heat Exchanger

Transfer of heat from region of high temperature to the region of low temperature from fluid to solid body happen due to process of convection. It depends on the both materials ability to transfer heat and the total temperature difference between the high and low temperature areas. It can be calculated as

Q=h*A*∆T

Here

Q represents the heat transferred

h represents the material convection heat transfer coefficient 

A represents the plate cross section area in contact with fluid 

∆Trepresents the temperature difference between fluid and liquid 

Overall heat transfer coefficient of flat plate heat exchanger

As explained in the working of flat plate heat exchanger first there will be a convective heat transfer between hot fluid and plate then conduction heat transfer between opposite sides of plate and at last convective heat transfer between plate and cold fluid. The total amount of heat transfer by the system is defined by the overall heat transfer coefficient of the system. Overall heat transfer coefficient can be calculated as below (Bari, 2015).

1/U=1/h1 + x/k + 1/(h 2)

Where

U represents the overall heat transfer coefficient

h 1 represents the convective heat transfer coefficient between hot fluid and plate

K represents the conductive heat transfer coefficient of plate

h 2 represents the convective heat transfer coefficient between cold fluid and plate

Selective Lase Melting, Laser Metal Deposition and Bounded Metal Deposition, a comprehensive comparison

Rick asks you which of the three possible metal AM processes would be best for the part: Selective Laser Melting (SLM), Laser Metals Deposition (LMD), or a recently developed process called Bound Metal Deposition (BDM) by a company called Desktop Metal.

The new design of bracket can be manufactured by any additive manufacturing process, but the material limitation has limited it to just three of the below mention process. Now best of them has to be recommended based on how it will manufactured product means pre-processing, processing and post processing. Other than this the process will also be evaluated on working principal/pattern and what advantages and limitations they have in processing the new design of bracket.

1. Selective laser melting SLM
2. Laser Metal Deposition
3. Bound Metal Deposition

Working

Selective laser melting will manufactured the bracket in two simple steps, first a layer of powder is spread on the machine table and then a laser will print a 2D shape of product by melting (that solidifies instantly) the power of desire shape. Laser metal deposition complete this in single step where a power is melted at the nozzle outlet by a laser and then spread by nozzle in a specific shape on the table. Similarly, bounded metal deposition also melts a binding material mixed with powder to deposit a layer of material on machine table.

Working pattern

Selective laser melting and laser metal deposition does not need any specific post processing process other than cleaning and surface finish if required but bounded metal deposition required binder curing process and melting process in furnace. Surface finish of the laser metal deposition is low as compared to selective layer deposition due to highly converged laser beam which only melts the metal where required in very controlled manner where laser metal deposition spread a paste of metal whose flow or spread cannot be controlled once it leave nozzle.

Bracket Manufacturing

Selective Laser milting, laser metal deposition and bounded metal deposition processes are very similar is terms of depositing the material to manufactured the bracket that is 2D layers of metal is deposited to develop a 3D product but steps in achieving this are very different. Is selective laser melting table used based moves downward with each layer finished where a new layer of powder is deposited which is then metaled by laser to create new 2D layer of metal where laser only moves on 2D plan. Laser metal deposition method use little complex approach where nozzle remain fixed in vertical position and table moves with six degree of freedom to deposit material layers. Bounded metal deposition work by depositing layers of material on static table and heat moves with 3 linear degree of freedom 3DOF.

Advantages and Limitations

Selective laser melting use laser which does not involve much of movement as compared to other two process means machine working is simple understand. Ability of this process to use multiple laser to manufacture one part or use each laser to manufacture multiple parts at once is most prominent feature which other two process lack. This makes an effective production rate of this machine for high volume batch production. Laser metal deposition seems to be the fastest process available with minimum steps required and fast speed of table and laser as compared to selective laser melting and bounded metal deposition but working of this process seems difficult to understand as compared to other two processes due to 6DOF required by table to manufactured product. Bounded metal deposition seems simple as compared to other two processes but number of steps involves in post processing make this process least favorite for this process due to high production rate.

Selection

So based on above discussion selective laser melting can be recommended as best process available for new bracket design as it has simple working process, less steps involve, processing multiple parts at once, high production rate and low or no post processing required.

3D printing and traditional supply chain

Additive Manufacturing AM also know as 3D Printing innovation may have an innovative effect on the current supply chain set-up.  The innovation has the ability to reduce the need for heavy-volume manufacturing facilities as well as low-level assembling staff, while dramatically lowering supply chain costs. We can 3D print on sale in terms of effects on stock and logistical support. 

3D printing ensures that we no longer need to keep the produced goods packed on the shelf or stored in depots.  We often produce the required product anytime we need it. Conclusively, this brings down the supply chain to its smallest bits, bringing improved efficiency to the network. 

These efficiency gains span the whole supply chain, from manufacturing costs to production, storage and to the part itself. Thus reducing waste, optimizing flexibility, and enhancing production run hours.

3D Printing and Traditional Supply Chain Relation

The conventional supply chain paradigm is centered on existing market limitations, rapid manufacturing efficiencies, minimum price requirements, bulk assembly staff, etc. However, 3D printing circumvents such restrictions. 

3D printing recognizes its usefulness in small-volume manufacturing, consumer-specific products, products capable of far greater functionality than is achievable via conventional methods. It thus excludes both bulk volume manufacturing facilities and low-level manufacturing staff, effectively reducing the supply chain to half. 

From the above perspective, shipping goods around the world is no longer financially effective because production can be achieved virtually anywhere at the equivalent value or even cheaper [4]. 

Modern resources are virtual information, wired and linked computer produces quicker and much more effective products than ever before. Which requires a modern supply chain framework?

Including regional procurement help, 3D printing technology has the ability to cut existing global supply chain systems and reconstitute them as a modern, decentralized network. In addition, the innovation establishes an intricate partnership between development, sales and marketing. 

Now, Consider the discrepancies between contemporary more conventional supply chain relative to what it might look like in the coming future with innovative 3D printers and the supply chain

3D printing impact on the supply chain 

Decentralize production in 3D printing

The technique's 'portable' evolution will allow corporations to take production sooner to local markets or to clients. As nothing more than a consequence, the production would be in favor of more central manufacturing centers as we'll see a turn away from industrial manufacture in low-cost regions. 

As a result of this, Companies would be able to manufacture parts closer to the people, rather than depending on imported products. This is particularly pertinent in periods of economic uncertainty, for instance during a trade war where the cost of importing products will escalate exponentially worldwide.

Drive product customization in 3D printing

In the new world, 3D printing technology is considered a tool-less method that provides the suppliers unparalleled flexibility to customize products and deliver it to mark of consumer individual needs and improve customer service. 

It would also lead to far more flexible supply chains that can respond rapidly to market shifts. Ultimately there would be an amalgamation of design, manufacturing and delivery into one supply chain mechanism with better participation of the consumer in the whole cycle of design and development.

3d Printing reduces complexity and improve time-to-market

3D printing utilizes the application Computer-Aided Design (CAD), which involves human involvement on both the rear and front ends. It is for sure that someone has to build the simple drawings that are normally kept in the form of CAD files for users to print an object even in your homes using a 3D printer. 

The suppliers and developers are actually selling their CAD files to interested people. 3D printing technology also integrates the number of parts and the manufacturing processes involved. 

It would have a huge impact on overall world supply chains, declining complexity faced during the production, reducing overall processing and production expenses which in-turn leads to improving the overall lea time and therefore boosting time-to-market.

Improve resource efficiency  in 3D printing

As things progress at present, products are made in wholly different locations than where they are to be used by the consumers, which sometimes comes up as both the producer and consumer are in separate continents. 

Such products need to be shipped to the end consumers, whether by aircraft, truck, rail or road, all of which utilize gases that generate polluting emissions. Through pervasive 3D printing technology, most products can be built on computers and produced right at the consumer’s door, thereby minimizing both shipping costs and environment pollution. 

Therefore, 3D printing is a cleaner form of manufacturing and is both power-efficient and expense-efficient. This generates nearly negligible disposal, reduces the chance of oversupply and surplus demand. Arguably, costs for 3D printing at this moment are high, but they do not remain that way long.

Rationalize inventory and logistics in 3D printing

During the current days when the development of the products is on-demand call, it reduces the need to move products around regions and countries.

It would have a huge effect on business services and logistics, along with the reduced number of SKUs needed for development, which would have the ability to transcend tariffs.

Through 3D printing, the output can become more flexible and will be more suited to adapt to consumer demands. That ensures shipping and storage would be less work-in-progress and completed goods and less mechanization of current inventory. 

Though the price per package could be higher with decreased capacity and less obsolete inventory, the average expense of the supply chain network can be smaller than that of the conventional supply chain. 

3D Printing facilitates a digital production system built-to-order, which in certain situations enables product selection to be held back throughout the supply chain phase. 

International networks of 3D printing facilities would provide opportunities to companies for rapidly adapting the changes in consumer demand and to easily and efficiently launch innovative goods. 

A new wave of product creativity could allow more flexible production methods. The innovation has the ability to reframe conventional forms of production in the longer term. The idea of producing goods in big, intricate facilities may become out of date as businesses adopt the more versatile additive development model.

Consequences for the logistics industry  

• The effects of this modern processing innovation for the logistics sector are immense:

• North America and Europe might theoretically be 'near-sourced' to a percentage of the products that were historically manufactured in China or other Asian markets. This will reduce the levels of shipping and air freight.

• Product configuration means a decrease in inventory prices when products are ordered. This will decrease the supply chain management needs.

• The manufacturer-wholesaler-retailer partnership may be profoundly influenced by build-to-order manufacturing strategies. The retail environment will be significantly different in the future too

• New logistics market will arise with regard to the collection and transportation of raw resources required for 3D Printing. As 3D Printers become more available to the general public, such materials will expand the home distribution demand

• The Transportation Supply Parts industry will be among the first to be impacted as billions of funds are actually expended on holding stock 

The Age of 3D Printing

The manufacturing sector has been associated with factory production, small machine-tools, assembly lines, and productivity gains after the 17-18th Century Industrial Revolution. Thus talking about production without tools and equipment, production lines, or supply chains is surprising. That's what the potential of 3D printing technology acquiring position appears,. Presently we can manufacture components, equipment, and devices right from our home or office. We just have to design, alter or import a virtual 3D model of an item to be prototyped using PC. 3D printers are often used to generate cost-effectively customized, overhauled components at the site where they are going to be utilized which was not possible earlier.

3D Printing

3D printing, often recognized as additive manufacturing – AM (as both terms are exchangeable now) is an engineering process used to create strong three-dimensional structures built in layers from a virtual illustration without a mold or cutting machine. 3D printing incorporates computer-aided design (CAD) to turn the design into a 3D model. The design is then fragmented into 2-D plans, which direct the 3D printer where the content layers will be deposited. The additive method adds successive thin layers of material to create a final 3-D model. Plastics, glass, rubber, polymers, paper, sand and glue blends and even human tissue can be used as input materials.  The development of a 3D artifact includes 3 simple ingredients-a computer model, feeding material and a 3D printer

Pros and Cons of 3D Printing

Advantages and disadvantages of 3D Printing

Pros	Cons
Reduced fixed-up costs and low tooling expenses	Slower manufacturing pace
Lesser manufacturing cost	Higher initial costs
Less manufacturing time and expense (increasing product-design rate)	Uncertain intellectual property obligations
Environmental-friendly: minimal CO2 impact	Variation in operation and quality
Cheaper cost for limited quantities and complicated crafted components	Restricted commodity range, sometime
Faster shipping period	Restricted product size
Complicated components fairly easy to porotype	Logistics uncertainty (3D printing incorporated to the supply chain)
Versatility including customer customization	Minimal large series efficiency.

Industrial application

As the platform gains popularity and versatility, AM's effect continues to grow, rendering it as a viable means of development in a number of industries [8]. Many businesses have implemented AM over the last few years and are able to pull out the actual advantages of the system. The pharmaceutical, automobile and aviation industry are among the markets with the highest scope for growth. AM allows items to be printed in distant areas, so the distribution of products is no more a constraint. Another main advantage of AM is Space Technologies [9,10]. NASA tested AM at zero gravity, hoping to create on-demand production for astronauts. This will require component parts to be produced in Space for maintenance and repair of the space station. It would also reduce the need for a spaceship to travel to the space station to supply components, thereby significantly reducing the turnaround time on replacements. The decreasing timeframe would entail lowering inventory and improving cost efficiency

3D printing “The future Technology”

Though 3D printing has been surfacing around the globe for years, recently in near years it has entered the mainstream for its uses. New 3D printing applications are continuously being created but the popularity of the applications has recently increased. Although 3D printing technology might appear as sci-fi, it's scientifically reality and only making presence known now.  Below are some of the implementations in the modern world:

3D Printing in Aerospace

The increasing cost of the infrastructure of aeronautics is best explained by the inefficient depreciation of tooling expenses over a small amount of production. In commercial 3D printing, regardless of whether you print a single item or a larger sequence, there is no effect on the amortization because you don't need to build a mold. Thus, for aerospace industries, the additive manufacturing method is well suited to fast series growth. You may be thrilled to hear that certain non-critical 3D printed pieces were already in use on airplanes. GE now has more than 300 3D printers and GE Aviation intends 100,000 additive parts to be produced by 2020. Seventeen 3D printed pieces have been mounted by the US Air Force on the C5 Super Galaxy and could save tens of thousands of dollars. Airbus / EADS, Rolls-Royce and BAE Systems are other elevated-profile consumers of the application. Boeing is also dreaming of designing entire planes using 3D printers on a wide scale.

3D Printing in Medical

There have been many 3D printing applications in the pharmaceutical field during the last few years.   These vary from bioprinting – where the synthesis of cells and enzymes produces tissue-like structures copying their natural equivalents – to therapeutic instruments such as prosthetics. The 3D printed prosthetics was an example of the durability of 3D printing. Production of prosthetics that incorporate a patient is difficult and expensive. Modulated prosthetics may be designed and manufactured at considerably reduced costs with 3D printing. The technique is now being used in the production of stock goods, such as hip and knee replacements, and specialized patient-specific devices, such as hearing aids, orthotic foot insoles, design prosthetics. Lead reports include Open Bionics, a UK-based maker of 3D prosthetic arms that received a £4.6 million investment in February 2019 to carry the company to the foreign market.

3D Printing in Automotive

Several automobile manufacturers are already using 3D printing to assist with prototyping. After the 1980s, Ford has employed 3D manufacturing technology. Modern processes will take multiple months and $500,000, according to Ford's official site, but for 3D printing, the same cycle requires four days and $3,000. Future prospects are virtually unlimited. Big Rep, a 3D printer service, introduced the first 3D printed motorcycle in January 2019. The ride, which isn't on the competition, has taken three days to print and costs only £2000.

3D Printing in Construction

While the innovation is in its development period, but major improvements have been made in the building sector with the usage of 3D printers as construction companies continue to realize the technology's usefulness. 3D concrete printing is quickly growing and is projected to hit $56.4 M by 2021. Increasingly firms are starting up to build new, creative ventures in the industry. Russian 3D printing company, for example, Apis-Cor has built a whole house in just 24 hours.

3D Printing and Challenges faced

As among the most revolutionary technologies to affect the manufacturing sector and the global supply network, 3D printing technology has got its name in the top evolved technologies. Many claim that the technology simply improves some facets of the manufacturing cycle, while others suggest that technology would revolutionize and substitute current operating systems. Either innovative or evolutionary, 3D printing technology is acknowledged as a significant development which will affect supply chains greatly. The aim of this paper is to address fundamental issues relating 3D printing technologies and the ways for modifying the production system and supply chain. For every emerging technological tool, AM production networks have problems that need to be tackled. Three main areas face challenges:

3D Printing in Engineering and technology

•Unique design criteria and load details for each particular AM system.

•Significant expenditure in technical education and system expertise is required

•Minor variations in material properties will hinder (sometimes) one-to-one substitution

•Comprehensive heat treatment and machining processes are currently at lower stages of mechanization

3D Printing and Management of data

•Long term regional or institutional differentiation between design and manufacturing entities requires safe shift of design which includes a development file, content specifications etc.
•Prototype might only be produced on a licensed printer and must therefore be allowed to print the component
•Design and development data must be trackable to original demands.

3D Printing Impacts in business

•Local production provides substantial availability / lead time advantages for spare parts delivery compared with central printing
•Enabling networks across decades of usage
•Preservation of intellectual property for concept and printing information
•Paves the way to alternative market models and operating modes

•Designs can be approved for printing by registered end users

Additive Manufacturing Model Advantages  

Capital saving in 3D Printing:

• Capital reductions.

• Removes necessity of massive inventories

• Eradicate the need for large processing plants

• Decrease shipping costs

• Minimize overhaul fines

• Improve the efficiency of an economic lot

• More cost-effective and reliable packaging options

• Deliver unique prototypes at reduced expense

• Reduce manpower

Good time response of 3D Printing:

• Removes the time difference between designing and production

• Reduced production times

• Allowing production on requests.

• Enhancing operation efficiency

• Less use of intermediates in supply chain process

Improvement in Quality in 3D Printing:

• Minimize manufacturing waste

• Enhance performance

• Integrate consumer input

• Deliver efficient goods in several markets

• Remove drag-and-drop surplus components

• Ambiguity management of demand

3D Printing Impact on Environment:

• Fewer harmful environmental effects

• Eliminating greenhouse gas emissions

In the new world, 3D printing commences, specifically as a way of creating prototypes. The latest technical developments and 3D printing technologies indicate that the innovation has the ability to radically change other aspects of real life. AM's effect on supply chains has several forms, such as streamlined manufacturing techniques, decreased resource loss for leaner processing, improved efficiency, decreased expense, quicker demand responses, and flexible processing capacity. 3D printing also sets up fresh markets and has the opportunity of reducing prices and rising earnings. As a consequence, supply chain will respond rapidly to business developments. It opens up fresh markets and provides other incentives for businesses seeking to increase productivity of manufacturing. AM streamlines conventional techniques significantly, which has the ability of becoming the standard over the coming decades. The platform allows design independence using regular CAD applications, which is not restricted to new production technologies. This also allows price efficient customization of goods. 

Though, 3D print development, needs to conquer one huge hurdle. To offer us more knowledge on all of its strengths and inventions, there are already perceptions about 3D printing from the time of its inception more than five years ago. The circumstance looks very different today as it presents the argument that 3D printing improves raw material use is deceptive. The 3D printing would have a huge effect on waste logistics.  As far as material savings and waste quantity is concerned   A well-designed production method utilizing 3D printing would be beneficial. A further false impression of 3D printing is that its key scope is for components constructed of plastics.  The technology's biggest advantage is the usage of a large variety of substances, not just plastics. For example, Metal 3D Printing possesses the capacity and considerable ability to generate complex, seamless components with physical properties that can often surpass those of traditionally produced pieces. Ultimately, the system has the power to transform the method we produce essential parts entirely.

Basics of Powder Metallurgy

Powder Metallurgy-Present and Future Scope: Production of components by taking initial methods in the form of powder is called as Powder Metallurgy. In this article, we will learn about the Present and Future Scope of Powder Metallurgy with its advantages and disadvantages in a detailed way.

CONTENTS of Powder Metallurgy:

• Introduction to Powder Metallurgy(PM)
• What makes the Powder Metallurgy exist?
• Powder Metallurgy Processes

1. Production of Powders
2. Mixing/Blending
3. Compaction
4. Sintering

• Advantages & Dis-Advantages
• Markets for Powder Metallurgy components
• Present and Future Scope
• Applications of Powder Metallurgy

A form of Powder Metallurgy existed in Egypt as early as 3000 B.C Used in 19thcentuary to produce Platinum and Tungsten wires. Utilized in Germany for producing Tungsten carbide cutting tools after 1stWorld war.

Definition:

Production of components by using initial methods in the form of powders is known as powder metallurgy. Failure of General alloy formation makes the powder metallurgy to exist.

POWDER METALLURGY Processes:

1.Production of Powders:

• Molten liquid is pressurized(P) and allowed to travel through a nozzle of diameter (Dn).
• The molten liquid will break into spherical droplets and are cooled in quench medium.
• They will be solidified and powder of particle size(Dp) is produced.

3.Compaction:

• Wet condition of powder mixture will be kept in the mould and is subjected to compression load under pressure.
• After compaction, the wet condition of powder mixture is called compact.
• The compact possesses low strength compared to the final strength of component called Green Strength.

4. Sintering

• The compact is heated to 80% of M.P. temperature.
• Due to this chemical bonds will form among atoms and thereby, strength increases.
• Sintering is performed in inert atm.(N2/Ar) or in the presence of vacuum to avoid oxidation.
• After sintering, the compact will achieve tremendous strength called as final strength.

Advantages of Powder Metallurgy:

• Alloys can be created from high MP metals including MO, W, Tantalum.
• Used for metals that are too hard to machine.
• In Super hard cutting tool bits, the tips will be coated with Fe3C, WC, SIC coatings by PMP.
• In the production of Ceramics (sustain a temp. of 3000’c), PMP will be used.
• Powder metallurgy components possess high compressive strength.

Dis-Advantages of Powder Metallurgy:

• Powder metallurgy components are expensive compared to General alloy formation method.
• Difficult to produce large & complex shapes with uniform density.
• Tensile strength is low.
• Al, Mg, Sb, Bi, As Ti powders, should not be used because they will undergo explosion at the time of compaction.

Markets for Powder Metallurgy components

• Around 80% of automotive applications are from powder metallurgy.
• 75% of components are used for transmissions.

Future scope of Powder Metallurgy Process

• Lightweight technology and engine downsizing in Automotive fields.
• Hitachi chemicals:
• Engaged in the development of wear-resistant parts, structural parts, magnetic parts (soft magnetic materials) for the development of high-performance parts as next-generation products.

Applications of powder metallurgy

• They are used for making cutting tools and dies.
• Used in making of machinery parts
• Powder metallurgical components are widely used in making bearings and bushes due to its self-lubricating property.

MOHAMMED SHAFI

Mohammed Shafi is a Mechanical Engineering Blogger by Passion and Assistant Professor by Profession. He want to Share his knowledge to the Young People by Presenting the GATE Sessions and all the concepts of Mechanical Engg. in a detailed way so that they can get best jobs in the future. For more info, Visit www.mechanicalstudents.com

Hydrodynamic design and performance analysis of underwater vehicles using CFD

Hydrodynamic design and performance analysis of underwater vehicles using CFD

Cite as: AIP Conference Proceedings 2116, 030009 (2019); https://doi.org/10.1063/1.5113993

Published Online: 24 July 2019

Talha Atta, Zaib Ali, Syed Mudassir Ali, and Emad Uddin

Abstract. Under Water Vehicles (UWVs) are extensively being used for variety of operations. Recently, there has been an increased interest in the design of autonomous unmanned underwater vehicles design (UUVs) as future generation submarines. The aim of this study is to investigate the effect of the various design parameters on the rotary coefficients of one such UWV i.e. a submarine SUBOFF model. The rotary coefficient has been calculated using the numerical simulations. The effect the wall roughness, linear velocity, rotation speed has been studied using the steady state Reynolds Averaged Navier-Stokes (RANS) simulations. The study helps to understand the underlying hydrodynamic phenomenon showing the dependence of these parameters on the hydrodynamics of the underwater vehicles.

CONCLUSION

A steady state CFD simulation of the rotary arm test on SUBOFF model was performed. Rotary coefficient obtain from graph of sways force and angular velocity shows that the establish models can provide approximation of result within 6.13 % of error when compared to experimental data. The parametric study of the SUBOFF model shows that the increase in linear velocity increases the pressure development on SUBOFF model while an increase in angular velocity will decrease the pressure development of SUBOFF model due to change in windward projected area, local drift angle and change in fluid flow velocity over the SUBOFF model. For the equal amount of change in linear and angular velocity, the linear velocity produces 15 % more pressure difference as compared to angular velocity. Increase in wall roughness produce very minute effect and decrease the pressure of SUBOFF surface. The future work aims to numerically study the effect of other parameters and then to use the results for design optimization using the optimization algorithms.