Heat Exchanger Test Rig - Research Proposal Example

HЕАT ЕХСHАNGЕR TЕST RIG Student Name: Abdulrhman Eisa AL-Maslamani Student ID.: 200659916 University: University of Leeds Supervisor: Prof. Timothy Cockerill Submission Date: 24-Nov-2014 Table of Contents 1.0 Introduction 3 1.1 Aims and objectives 3 1.2 Phenomenon Simulation Description 3 2.0 Literature review 4 2.1 Background 5 2.1.1 plats heat exchanger 5 2.1.2Advantages of using plats heat exchanger 5 2.1.3 Size and output 5 2.2 Methodology 6 2.2.1 Selecting the heat exchanger design 6 2.2.2Construction of Plate heat exchanger 7 2.2.2.1 Components of the heat exchanger 8 2.2.2.2 Plate heat exchanger assembly 9 2.2.3 Heat of Fluid Theory 10 2.2.4 Practical Heat Transfer Control  11 2.3 AIC Unique Solutions 12 4.0 Gantt Chart 15 5.0 Project risk assessment 16 6.0 Results and discussion 18 6.1 Pressure distribution 18 6.2 Velocity distribution 18 6.3 Temperature distribution 18 7.0 Conclusion 19 8.0 References 20 1.0 Introduction Heat exchange works using natural phenomena, which occurs in the entire environment. Practically, these systems help in driving energy exchange systems as well as weather cycles between ecosystems. Tapping its ability using proper heat exchange control systems, it has been used in the industries for more than a century. In most applications, heat exchangers have control on how heat transfer occurs in fluids. The major applications where heat exchangers are used include solar heating, domestic water heating, general industrial process control, pool heating, food processing, radiant floor heating, marine applications, general industrial process control, and others. Oil-to-oil plate heat exchanger using counter flow method of heat transfer is the most efficient mode of heat transfer. In this system, heat is transferred from a hot medium 2 (internal oil) to a cold Medium-1 (cold in coming oil). If oil is the fluid passing through the heat exchanger, then this type of heat exchanger is called an oil-to-oil heat exchanger. In this case, both medium of heat transfer is oil for oil-to-oil heat exchanger. As hot oil moves through the heat exchanger flow tubes, it passes and exchanges heat with cold oil flowing in the opposite direction. 1.1 Aims and objectives The main aim of this project is to study, design and understand operation and the working processes in heat exchanger test rig. In this project I will decides to take the gasket plate heat exchangers exactly in the oil/water flue. 1.2 Phenomenon Simulation Description The heat exchanger comprises of a buddle of tubes installed in a rectangular enclosure. The design and flow of the heat transfers fluids in the heat exchanger are as indicated in figure 1. In this system, cold oil flows through the inner tubes while the external section of tubes are into contact with hot oil from the motor. This exchanger has four sections, separated by baffles placed internally and a partition plate (Kuppan, 2013, 138). The baffle helps in controlling the hot oil to flow in the required path. The separating plate and the end creates a partition between the cold and the hot oil diving the heat exchanger in two sections while distributing oil in the two sections of the heat exchanger. Hot oil from the motor goes to the middle two sections of the heat exchange (second & third sections) while the cold oil flows through the inner tube, and thermal energy is exchanged at this section. Cooled hot oil that leaves the first and the fourth compartment of heat exchanger recirculated to the motor. On the other hand, cold oil leaving the tube and it is discharged to the ambient. Figure 1: Counter flow pipe Fluid flow system is expressed using equation of continuity of momentum and energy flow, which is solved using finite state steady state flow for oil turbulent flow using ideal gas equation. 2.0 Literature review In designing plate heat exchanger, two metal plates are used in the transfer of heat between fluid that a flowing in a counter current flow. This has a higher advantage compared to the conventional heat exchanger, where media fluids are exposed to very broad area since the fluids are all over the plates. This alleviates the heat transfers process to increase speeding up the rate of temperature increase. Millions of combined boilers hot water sections are composed of the small braxed versions and this makes plate heat exchange very common in these sectors. The idea on which the heat exchanger works on is application of piping or use of vessel that contains hot or cold fluid flowing. The exchanger has a pipe that is coiled where one fluid flows across the chamber that has the other fluid. Normally, the pipe walls are made of metallic material and they have a high thermal conductivity. This alleviates the heat interchange, while the outer casing of the larger heat exchanger chamber is made of coated plastic material to provide thermal insulation to prevent loss of heat from the heat exchanger. 2.1 Background Oil-to-oil heat exchanger systems uses natural stack ventilation and usually requires mechanical ventilation. Oil used in these systems, in most cases flow through the oil-handling units, this enhance the supplementary and filtering heating/cooling processes. To monitor the temperatures a simple controller monitors flowing in and out of the system as well as temperatures indoor. The tube used in designing this system are made of, the tube is fitted in a clay lining to ensure that there is little or no heat loss and increase thermal heat loss resistance. 2.1.1 plats heat exchanger This type of heat exchanger is made of a series of plates; where the thin metal plate compressed in order with two ends of pressured plats. Normally these types of heat exchangers are robust and provide low pressure and low temperature. When designing this system, thermal features are considered. However, some variations like having all ends of the tubes connected to plenums. 2.1.2 Advantages of using plats heat exchanger They have high values for the overall heat exchanger coefficient. It is easy maintain and clean. There is low fabrication cost. There is flexibility in used. The plate heat exchanger can operate with relatively small temperature differences. 2.1.3 Size and output The most favorable pipe length is the work of the pipe diameter and velocity of the oil velocity. Normally, the size of plate heat exchanger is 50 mm2 as Alfa level mention in the gasket plate heat exchanger handbook. However, the Maximum heat transfer surface is 38m2 2.2 Methodology The gaskets plate heat exchanger design that will be used should follow the design shown in figure 2 where there are two media of exchange. In this case, the medium 1 and medium 2 is oil. However, the flow in this system is designed to use counter current flow of oil. Figure 2: cooling medium flow direction 2.2.1 Selecting the heat exchanger design Referring to the flow indicated in figure 2 above, this section shows the typical steps used in designing of an oil-to-oil heat exchanger: Select the type of heat exchanger by deciding the number of passages to use Decide which section where inlet and outlet temperatures (t1, t2, T1 and T2) will flow for the entire heat exchanger. Based on the application of the heat exchanger, these values are specified. Using the following formulae, the heat load is calculated as following: …………….. (1) Where, H - Total heat exchanger heat load & – Mass of oil for side 1 & 2 (flowing per unit time). & – oil flowing specific heat in side 1 & 2. Log Mean Temperature Difference (LMTD) is calculated as follows: ………………………………………..… (2) The overall heat transfer coefficient (U) is calculated as follows: …………………………………………………………. (3) Where, – Oil convection heat transfer coefficient. – Tube material thermal conductivity To calculate the required surface area, the following equation is used: …………………………………………………… (4) Where, – Required surface area. When the surface required is determined, and then the oil-to-oil heat exchanger is sized for design. 2.2.2Construction of Plate heat exchanger A plate heat exchanger comprises of a several of heat transfer plates, which are placed to form a completed unit between a loose pressure plate and a fixed plate. Every plate of the heat transfer has gasket arranged in such a way that it gives two distinct channel systems. The arrangement of the gaskets (ring and field gaskets) leads to flow through in single channels, this way the primary and secondary flow media work in a counter-current flow. Because of the gasket design, the media cannot mix and this ensure that the system is more efficient in heat exchange. The plates used are folded is such a way that they can create fluid turbulence as the fluids flow through the system unit. This turbulence, in association with the ratio of the volume of the media to the size of heat exchanger, gives an effective heat transfer coefficient. 2.2.2.1 Components of the heat exchanger The main components of the plate heat exchanger are made up of fixed end plate, loose pressure plate that have bars connected to them and connections. From the top carrier bar, hung the plates of the plate heat exchanger. In addition, these bars they help in positioning the heat transfer plates. Lastly, the single plates are tied together forming a plate pack. For gasketed plate heat exchangers, they can be prepared in standardized sizes. Generally, the main materials that can be used in making gaskets include nitrile rubber, which can be used for general purposes since it is resistant to oil. The other material that can be used in making gaskets is EPDM, which is used generally and it is applicable in higher temperatures. Lastly, heatsealf material is used in making gaskets that can work at high temperatures especially in steam heating systems. In this project, in the design of the heat exchanger, nitrile rubber will the main material for the making of the gasket. This material will be suitable for the system, since the system is oil based and Nitrile rubber is the suitable gasket material. Figure 3: Plate heat exchanger 2.2.2.2 Plate heat exchanger assembly Using the separate components of the heat exchanger, I will assemble the components discussed the section above and test for any pressure loses and oil leakage. Using gaskets in this system will make it easier for the servicing procedures on the heat exchanger. This was, during inspections and cleaning it will be easy to work on the system. The figures below indicate step by step procedure used in the assembly of the plate heat exchanger: Figure 4: frame assembly Frame parts are joined together. This contains only the pressure plates, the frame, and two carrying bars for the upper and lower sections. The first plate to hang in the frame is the end plate. Figure 5: positioning plates From the above figure, plates are placed in frame as per the specification of the user. This way, it is easy to manage the pressure and products loses from the system. Figure 6: joining the system using bolts After fitting the plates and the plate pack properly tightened, the heat exchanger is tested for pressure and products losses from the sections of the plates that might have been left out in the design assembly. 2.2.3 Heat of Fluid Theory The principle of heat transfer is based on heat exchange between cold and hot fluid, where cold fluid gains heat from the hot fluid. This system has a material that conducts heat separating the fluids that flow in the separate pipes. Total heat of the flowing fluid is calculated using the equation below:            Total heat load  Mass flow rate of fluid.  Specific heat of fluid (at constant pressure). Fluid temperature change This equation gives the heat exchanger system theoretical heat developed from temperature change, () at a given mass flow rate, () and fluid’s specific heat, (). 2.2.4 Practical Heat Transfer Control  From theoretical heat transfer, the amount heat generated by the fluid is the total amount of heat moving in and out of the fluids. On the other hand, practical heat transfer works as the function of heat exchanger physical geometry, the condition of the fluid and its material composition.  Maximum potential heat that is transferred through the heat exchanger are given by the equation below:     Where: Overall heat transfer coefficient Surface area Thermodynamic interactions taking place within the heat exchanger fluids helps in determining Practical Heat Transfer. In addition, overall  is determined by the equation that is particular to the geometrical shape of the Heat Exchanger. The function for this equation is from members that are dimensionless like Prandlt Number (), Reynolds Number (), as well as applying other fluid flow parametric quantities. The total U determined within heat exchanger surface area A flows across the fluids exchange heat. On the other hand, LMTD of the flowing fluids (hot and cold fluids) in the counter flow exchange system, which is determined by the formula:       = hot fluid inlet temperature = cold fluid outlet temperature  = hot fluid outlet temperature  = cold fluid inlet temperature The total heat from Practical heat is compared with theoretical, , to determine whether the heat Exchanger is able to attain the requirements of the system. 2.3 AIC Unique Solutions From the above equations, it is easy to understand the performance of the heat exchanger irrespective of the material and type. To choose the best heat exchanger for a given application, it is a must to consider variables such as material reaction with the fluid, design rating, performance optimizations, requirements of certification, maintenance and installations constraints. 3.0 Project plan 3.1 Project goals The main goal of this project of heat exchanger is to study, design and understand the operation of the heat exchanger. When the designer understands the operation of the equipment, he will be able to design better equipment, which would be easy and efficient t to use. 3.2 project deliverables Some of the things this project has to deliver include -Understanding how a heat exchanger works -Knowing the right material components of a heat exchanger that would increase efficiency -Designing a better heat exchanger using the modern technology -Designing heat exchanger that would be ease to be maintained and operated by the users. 3.3Project schedule 1st month -Consultation from my project supervisor -Choosing on which project to work on 2nd month -Carrying out some literature review of the project 3rd month -Sketching the plan heat exchanger -Designing the heat exchanger -Consultation with the supervisor -Readjustment of the plan after consultation 4th month -Check the availability of the materials in the lab -Collection of the necessary materials -Drawing and cutting them according to the design 5th month -Construction of the heat exchanger as per the plan -Testing the functioning of the het exchanger 6th month - results analysis -Writing the report for the project 4.0 Gantt Chart 5.0 Project risk assessment When designing a heat exchanger, one should consider a number of risks that may occur during the use of this project. This heat exchanger is exposed to both high and low temperatures. It carries fluids such as oil; it has various components made from different materials and the entire system of the heat exchanger is quite complicated. Therefore, it implies that the heat exchanger could face various risks that can either cause damages to the entire equipment or cause damages to the users. It is wise for the developer of the heat exchanger to assess the risks that may emerge. It will make the user aware in advance to avoid certain actions that may make the equipment more exposed to particular risks. Risks assessment helps the users to make good use of the equipment by taking precautions of the risks factors. In this project of developing a heat exchanger, some of the risks factors that would assessed include technology, safety, maintainability, operability and the cost. The technology that should used on this heat exchanger should be build from the known technology so that other experts can easily catch up with concepts used in building this new equipment. This would enable them to repair the equipment when it is damaged. Risk factor Low risk Medium risk High risk Technology -Modern technology used -The technology is build from the known concepts -little or no testing required - The state of art used is proven - Some proof of testing is required -The equipment has both quality and non-quality materials -Unproven technology applied -Extensive proof of testing required before using the equipment -The concepts used in building are outdated Poor quality of materials were used in building the heat exchanger Safety -Qualified and approved designer -Worker and user health safety considered -The designer of the heat exchanger has exemplary safety records -A qualified but not yet approved designer -Existing hazards are well understood but no good precaution laid -Worker and user health safety is integrated in the building of the heat exchanger -Presence of multiple hazards -There are no user health safeties integrated in the construction process. - Maintainability -Ease to be maintained by unskilled person -Ease to clean and repair the broken parts by anyone -All the parts of the equipments can be accessed for easy repairing and cleaning -Some people find it hard to maintain the equipment -Some internal parts are hard to access when cleaning the equipment -Some worn out parts are hard to replace -Only skilled people can maintain the equipment -most parts cannot be accessed when cleaning the equipment - Operability -Many users find it easy in operating the heat exchanger -the machine are easy to install -The equipment can easily fit with other external appliances -Few users find it hard in using the equipment -The equipment some breaks easily when exposed to extreme environment such as heat -Easy to dismantle and assemble - Only skilled individuals can operate this equipment -The equipment breaks easily even at no extreme conditions -The equipment does not fit with other home appliances 6.0 Results and discussion 6.1 Pressure distribution The area with high pressure is the section with the plate that separates cold and hot fluid. This high-pressure difference in this region is attribute to change in momentum caused by the plate to the cold fluid. As the cold oil enters the tube, it is at high speed; however, as it moves towards the exit, this pressure reduces drastically. This slow change is pressure is due to the high friction exerted to the wall of the tube caused by flowing oil. Due to jet effect caused by the exiting cold oil from the tube, there is a small pressure reduction in the tube. 6.2 Velocity distribution As the fluid passes through the inlet of the tube, a high-pressure variation is caused by the resistance of the wall at the end of the separating plate. During oil intake, the incoming oil stream hits the separating plate. Due to the high pressure on the separating plate, most oil is force into tube and flows back towards the intake section. Near the entry of the tube, oil is usually at a high speed but because of the contraction of the inlet tube, this velocity reduces drastically. This means, as the oil moves from the intake towards the exit, velocity reduces gradually. From the observations made, velocity is low neat the dead zone where velocity is lowest. 6.3 Temperature distribution To analyze hot oil inlet temperature effect on temperature distribution in the entire heat exchanger, a study simulation is conducted and carried out ensuring that the 2nd section and the 3rd section are determined. Due to these observable temperature changes in the heat exchanger, the resulting pressure and velocity vary drastically. 7.0 Conclusion An experimental method used on prediction of the required distribution of velocity, pressure and temperature has been conducted using the CFD software to acquire the final measurement. All the value that were observed from the prediction in the simulation were then compared with the experimental values (Ramesh, and Dusan, 2003, 69). Then a good conclusion was attained. From the calculated values all, the temperatures for the inlet oil and the out oil were compared and found to be close to the experimental values. CFD was used to in the experiment to ensure that thermal performance we optimized to improve the efficiency of the heat exchanger used. Further, CFD can be used in the process of reducing the design cycle and ensure that the computation process is quick to work on. 8.0 References Bengt, S. and Manglik, R. M., (2007), Plate Heat Exchangers: Design, Applications and Performance. Southampton: WIT Press. Branan, C. R. (2011) Rules of Thumb for Chemical Engineers. New York: Gulf Professional Publishing. 78 Hesselgreaves, J.E, (2001) Compact Heat Exchangers: Selection, Design and Operation. New York: Gulf Professional Publishing. 79 Juvinall, R. C. and Kurt, M., (2006) Fundamentals of Machine Component Design. 4th Edition. New York: Wiley Global Education. Juvinall, R. C. and Kurt, M., (2011) Fundamentals of Machine Component Design. 5th Edition. New York: Wiley Global Education. Juvinall, R.C. and Kurt, M., (2012) Machine Component Design. New York: Wiley. Kidnay, A. J. and Parrish, W. R., (2006) Fundamentals of Natural Gas Processing. New York: CRC Press. Kong, L. B., et al, (2014), Waste Energy Harvesting: Mechanical and Thermal Energie. New York: Springer Science & Business Media. Kuppan, T., (2013) Heat Exchanger Design Handbook, Second Edition. New York: CRC Press. Maurice, S. and Oran, T. L., (2012) Heat Exchanger Equipment Field Manual: Common Operating Problems and Practical Solutions. New York: Gulf Professional Publishing. Ramesh, K. S., and Dusan, P. S., (2003) Fundamentals of Heat Exchanger Design. New York: John Willey & Sons. Sadik, K. and Hongtan, L., (2002). Heat Exchangers: Selection, Rating and Thermal Design. 2nd Edition ed. New York: CRC Press. Stewart, M and Oran, T. L., (2012), Pressure Vessels Field Manual: Common Operating Problems and Practical Solutions, New York, Gulf Professional Publishing. Wang, J.Y., (2008). Pressure drop and flow distribution in parallel-channel of configurations of fuel cell stacks: U-type arrangement. Int. J. of Hydrogen Energy 33 (21): 6339–6350. Wang, J.Y., (2010). Pressure drop and flow distribution in parallel-channel of configurations of fuel cell stacks: Z-type arrangement. Int. J. of Hydrogen Energy 35 (11): 5498–5509 Wang, J.Y., (2011). Theory of flow distribution in manifolds. Chemical Engineering J 168 (3): 1331–1345. Appendix I Task start data # of days to complete stop data List all the type of the heat exchanger 09/10/14 7 15/10/2014 Compare the size and the advantage of the heat exchanger 16/10/2014 3 22/10/2014 Sketch of the right heat exchanger 19/10/2014 4 29/10/2014 Compare the Brazed and gasket plate heat exchanger 29/10/2014 4 05/11/2014 Identify suitable "off-the-shelf" heat exchanger 30/10/2014 5 04/11/2014 the availability of the gasket heat exchanger 30/10/2014 5 04/11/2014 Literature review 05/11/14 147 01/04/15 draft form the interim report 01/11/14 18 19/11/2014 Calculation outlet temperature and flow rate 07/11/14 30 07/12/14 Proof reading for the interim report 19/11/14 5 24/11/14 Designing heat exchanger 26/11/14 14 10/12/14 Designing test rig and tests 26/01/15 10 05/02/15 Manufacturing heat exchanger 30/01/15 30 01/03/15 Building test rig 28/02/15 30 30/03/15 Modifying the test rig (optional) 29/03/15 14 12/04/15 Testing 02/04/15 7 09/04/15 Results analysis 09/04/15 7 16/04/15 Writing the final report 01/04/15 30 01/05/15 Proof reading for the final report 01/05/15 4 05/05/15 Read More

The separating plate and the end creates a partition between the cold and the hot oil diving the heat exchanger in two sections while distributing oil in the two sections of the heat exchanger. Hot oil from the motor goes to the middle two sections of the heat exchange (second & third sections) while the cold oil flows through the inner tube, and thermal energy is exchanged at this section. Cooled hot oil that leaves the first and the fourth compartment of heat exchanger recirculated to the motor.

On the other hand, cold oil leaving the tube and it is discharged to the ambient. Figure 1: Counter flow pipe Fluid flow system is expressed using equation of continuity of momentum and energy flow, which is solved using finite state steady state flow for oil turbulent flow using ideal gas equation. 2.0 Literature review In designing plate heat exchanger, two metal plates are used in the transfer of heat between fluid that a flowing in a counter current flow. This has a higher advantage compared to the conventional heat exchanger, where media fluids are exposed to very broad area since the fluids are all over the plates.

This alleviates the heat transfers process to increase speeding up the rate of temperature increase. Millions of combined boilers hot water sections are composed of the small braxed versions and this makes plate heat exchange very common in these sectors. The idea on which the heat exchanger works on is application of piping or use of vessel that contains hot or cold fluid flowing. The exchanger has a pipe that is coiled where one fluid flows across the chamber that has the other fluid. Normally, the pipe walls are made of metallic material and they have a high thermal conductivity.

This alleviates the heat interchange, while the outer casing of the larger heat exchanger chamber is made of coated plastic material to provide thermal insulation to prevent loss of heat from the heat exchanger. 2.1 Background Oil-to-oil heat exchanger systems uses natural stack ventilation and usually requires mechanical ventilation. Oil used in these systems, in most cases flow through the oil-handling units, this enhance the supplementary and filtering heating/cooling processes. To monitor the temperatures a simple controller monitors flowing in and out of the system as well as temperatures indoor.

The tube used in designing this system are made of, the tube is fitted in a clay lining to ensure that there is little or no heat loss and increase thermal heat loss resistance. 2.1.1 plats heat exchanger This type of heat exchanger is made of a series of plates; where the thin metal plate compressed in order with two ends of pressured plats. Normally these types of heat exchangers are robust and provide low pressure and low temperature. When designing this system, thermal features are considered.

However, some variations like having all ends of the tubes connected to plenums. 2.1.2 Advantages of using plats heat exchanger They have high values for the overall heat exchanger coefficient. It is easy maintain and clean. There is low fabrication cost. There is flexibility in used. The plate heat exchanger can operate with relatively small temperature differences. 2.1.3 Size and output The most favorable pipe length is the work of the pipe diameter and velocity of the oil velocity. Normally, the size of plate heat exchanger is 50 mm2 as Alfa level mention in the gasket plate heat exchanger handbook.

However, the Maximum heat transfer surface is 38m2 2.2 Methodology The gaskets plate heat exchanger design that will be used should follow the design shown in figure 2 where there are two media of exchange. In this case, the medium 1 and medium 2 is oil. However, the flow in this system is designed to use counter current flow of oil. Figure 2: cooling medium flow direction 2.2.1 Selecting the heat exchanger design Referring to the flow indicated in figure 2 above, this section shows the typical steps used in designing of an oil-to-oil heat exchanger: Select the type of heat exchanger by deciding the number of passages to use Decide which section where inlet and outlet temperatures (t1, t2, T1 and T2) will flow for the entire heat exchanger.

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