ME495 Lab 05_ Heat Plate Exchanger

pdf

School

San Diego State University *

*We aren’t endorsed by this school

Course

495

Subject

Mechanical Engineering

Date

Apr 3, 2024

Type

pdf

Pages

15

Uploaded by ChiefDeerMaster1083

Report
Heat Plate Exchanger ME 495: Mechanical and Thermal Systems Lab Section 05 Authors: Soeung Khanitha, Smith Emilee, Sichantha Jack, Taylor Charles Instructor: Dr. Hamid Nourollahi February 5, 2024
1 Table Of Contents Objective of Experiment ( Khanitha Soeung and Jack Sicantha) .................................................................. 2 Equipment ( Jack Sichantha ) ......................................................................................................................... 4 Experimental Procedure ( Khanitha Soeung ) ................................................................................................ 5 Experimental Results (Emilee Smith and Charles Taylor) ............................................................................. 5 Sample Calculations: (Run 1) (Charles Taylor) ............................................................................................. 8 Discussion of Results (Charles Taylor) .......................................................................................................... 9 Lab Guide Questions (Emilee Smith) .......................................................................................................... 10 Conclusion (Emilee Smith) .......................................................................................................................... 11 Appendix ( Khanitha Soeung ) ..................................................................................................................... 12
2 Objective of Experiment ( Khanitha Soeung and Jack Sicantha) This experiment will illustrate indirect temperature regulation through the transfer of heat from one fluid stream to another that is being facilitated by a solid wall ( fluid to fluid heat transfer ). The primary objective is to assess the heat transfer coefficient. This is a key indicator of heat exchanger efficiency across multiple flow rates. This experiment utilizes the HT30XC Heat Exchanger Unit and HT32 Unit ( Plate Heat Exchanger ) designed by Armfield Limited in England. The thermocouples will be positioned along the tubes. One will be in the hot stream and the other will be placed in the cold stream. These thermocouples will provide temperature readings for the fluid at various points. This energy exchange in each of the streams will be calculated to assess the system's overall efficiency. It is hypothesized that increasing the flow rate of the cold fluid will enhance the heat transfer coefficient. Thus resulting in improved overall efficiency within the heat exchanger system. Equations and Symbols (Jack Sichantha) Hot fluid inlet: T1 Hot fluid outlet: T2 Cold fluid inlet: T3 Cold fluid outlet: T4 Equation 01: Convert hot fluid volume flow rate Equation 02: Convert cold fluid volume flow rate Equation 03: Change in hot water temperature
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
  • Access to all documents
  • Unlimited textbook solutions
  • 24/7 expert homework help
3 dT = Change in temperature T(hot, in) = Temperature of water at hot inlet T(hot, out) = Temperature of water at hot outlet Equation 04: Change in cold water temperature dT = Change in temperature T(cold, in) = Temperature of water at cold inlet T(cold, out) = Temperature of water at cold outlet Equation 05: Heat emitted by hot fluid Q. = Heat rate m. = Mass flow rate cp = Specific heat capacity dT = Change in temperature Equation 06: Heat absorbed by the cold fluid Q. = Heat rate m. = Mass flow rate cp = Specific heat capacity dT = Change in temperature
4 Equation 07: Overall system efficiency η = Overall Efficiency Q.(emitted) = Heat (amount) emitted Q.(absorbed) = Heat (amount) absorbed Equation 08: Overall Heat Transfer Coefficient h = Overall heat transfer coefficient Q.(emitted) = Heat (amount) emitted A = Flow area LMTD = Logarithmic mean temperature difference Equation 09: Logarithmic mean temperature difference LMTD = Logarithmic mean temperature difference dTA = Difference in temperature between the T3 and T4. dTB = Difference in temperature between the T1 and T6. Equipment ( Jack Sichantha ) Armfield HT30XC Heat Exchanger Unit
5 Uses metal plates to transfer heat between two fluid streams without mixing. This ensures a precise temperature control for multiple applications. Armfield HT32 Unit ( Plate Heat Exchanger ) Plate heat exchanger that complements the Armfield HT30XC unit by facilitating the transfer of heat between two varying fluid streams without them coming into direct contact with each other through a series of plates. Experimental Procedure ( Khanitha Soeung ) To begin the lab 05 experiment according to the lab guide provided by Dr.Hamid Nourollahi, the system must be primed according to the defined setup. Proceed to Launch the Armfield HT31 Plate heat exchanger software, select the ‘counterflow’ option, and proceed to load the configuration. View the diagram, and have one other student set the hot water flow to 2.5lit/min in ‘automatic mode’. Then set the hot water temperature to 50 degrees Celsius. Adjust the cold water valve to 100% open. Make sure to confirm the setup with the TA. Proceed to open the hot water valves, turn on the main power switch, and begin the unit. After that portion, activate the motor and heater while waiting for the hot water to reach the designated temperature. Then open the cold water supply valve to achieve a 3L/min flow rate, begin data collection, and save the obtained results. Continue to repeat the procedure for two additional cold water flow rates at 2L/min and 1.5L/min. End the experiment by closing the cold water valve, turning off all power, and disconnecting all connections. Save the data obtained on a flash drive as an Excel 5.0 file. Experimental Results (Emilee Smith and Charles Taylor) Table 01:Average Efficiency and Error Across Different Flow Rates Flow Rate (L/min) Overall Efficiency (%) 3 103.15 2 105.48 1.5 99.37
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
  • Access to all documents
  • Unlimited textbook solutions
  • 24/7 expert homework help
6 Table 02:Average Heat Transfer Coefficient and LMTD Across Different Flow Rates Flow Rate (L/min) Logarithmic Mean Temperature Difference LMTD Heat Transfer Coefficient 3 14.175 7086.04 2 14.083 6311.45 1.5 13.865 5637.38 Figure 1 Heat Power vs. Flow Rate Plot
7 Figure 2 Temperature Change vs. Flow Rate Plot Figure 3 Overall Efficiency vs. Flow Rate Plot
8 Sample Calculations: (Run 1) (Charles Taylor) Table 03: Data from Experiment Property Temp at hot inlet Temp at hot outlet Temp at cold inlet Temp at cold outlet Hot water flow rate Cold water flow rate Symbol T1 T3 T4 T6 V. V. Units C C C C L/min L/min Value 50.0 37.3 21.8 32.9 2.60 3.14 Table 04: Fluid Properties Property Specific Heat Capacity Density, Hot Fluid Density, Cold Fluid Symbol cp rho rho Units KJ/kg*K kg/m3 kg/m3 Value 4.18 989.18 997.51 Calculations: Find mass flow rate: Equation Mass Flow Rate: . ?. = 𝑉. * ?ℎ? m. = 0.043 kg/s for hot fluid and 0.052 kg/s for cold fluid. Find Temperature Change: Equation 3: ?𝑇(ℎ??) = 𝑇(ℎ??, 𝑖?) * 𝑇(ℎ??, ???) Equation 4: ?𝑇(????) = 𝑇(????, ???) * 𝑇(????, 𝑖?) dT = 12.7 degrees C for hot fluid and dT = 11.1 degrees C for cold fluid. Find heat emitted and absorbed Equation 5: 𝑄. (??𝑖????) = ?. (ℎ??) * ??(ℎ??) * ∆𝑇(ℎ??) Equation 6: 𝑄. (????????) = ?. (????) * ??(????) * ∆𝑇(????) Q. (emitted) = 2278.6 W
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
  • Access to all documents
  • Unlimited textbook solutions
  • 24/7 expert homework help
9 Q. (absorbed) = 2418.9 W Find heat loss Equation Heat Loss Final: 𝑄. (?𝑖???) = 𝑄. (??𝑖????) − 𝑄. (????????) Q.(final) = 140.3 W Find Logarithmic (LMTD) Equation 9: ??𝑇𝐷 = (?𝑇? − ?𝑇?)/??(?𝑇?/?𝑇?) LMTD = 16.29 Find Overall heat transfer coefficient Equation 8: = 𝑄. (??𝑖????) / (? * ??𝑇𝐷) h = 6995.2 Find Overall efficiency Equation 7: η = 𝑄. (????????) / 𝑄. (??𝑖????) * 100% η = 106.2 Discussion of Results (Charles Taylor) Figure 1, Heat Power vs. Flow Rate Plot represents the relationship between heat rate and the flow rate of the cold fluid in the system. One of the main takeaways from this data is that the heat transfer amount directly increases with an increase in cold water flow rate. This increase implies that the higher the flow rate the more heat will be transferred. This is important if a team is using this concept on a large scale because increasing the flow rate may make the entire process of heat transfer more efficient and effective. Figure 2, Temperature Change vs. Flow Rate Plot represents the relationship between temperature change
10 and the flow rate of the cold fluid in the system. This is an important graph because it describes the behavior of the relationship between temperature change and the flow rate. This information is useful in calculating the heat transfer coefficient of the overall system. Figure 3, Overall Efficiency vs. Flow Rate Plot shows the relationship between overall efficiency and the flow rate of the cold fluid in the system. This information is representative of the error in the system. Furthermore, this can be useful in real life situations when one is trying to minimize the overall loss from the system. The heat transfer coefficient is representative of the proportionality between heat transfer rate and temperature change. This was shown to decrease as the cold water flow rate increased. This could be due to several factors. It is related to the four factors that affect change in the heat transfer of this system: Flow rate, Temperature change, Fluid properties, and System geometry. The primary two we are affecting change in are the temperature change and the flow rate. Systematic and random error is represented in this report by the efficiency of the system and the randomness within the averages of the data. As shown in Figure 3, efficiency increases overall as one increases the cold water flow rate. This said, the efficiency did not drastically increase, and it also was somewhat random amongst the different flow rates. This leads one to the conclusion that cold fluid flow rate does not have an extremely strong effect on the efficiency of the system. The hypothesis included in the objective section of this report states that increasing the cold fluid flow rate will in turn increase both the heat transfer coefficient and the overall efficiency of the system. This is true based on the results shown above, both Table 2 and Figure 3 indicate that increasing the flow rate will increase these other factors. Lab Guide Questions (Emilee Smith) 1. Did the heat exchanger remove more or less heat from the hot stream as the flow rate of the cold water increased? As the flow rate increased, the heat exchanger removed more heat from the hot stream. This is evident in Figure 1 which illustrates, in this case, the power (or heat) emitted from the hot stream vs the flow rate of the cold water.
11 2. Did the system efficiency increase or decrease as the cold water flow rate increased? With the increase in cold water flow rate, system efficiency also increased as shown in Figure 2. 3. Were there any systematic or random errors that affected your measurements in this experiment? Discuss in detail and suggest innovative ways to minimize such errors. Because the data collected from the experiment is mostly computerized, the errors would involve things such as possible issues with sensors or the technology. Calibrating prior to collecting data would help improve this. Other issues may involve improper or worn sealing, water loss, or problems with the piping. Minimizing these errors would include regular maintenance of the equipment. Conclusion (Emilee Smith) The objective of this experiment was to evaluate the heat transfer coefficient at several different flow rates between hot and cold water streams with a solid wall separating them. As the fluids flow on either side of the plates, heat transfers between them, the temperature of the cold fluid increasing and the temperature of the hot fluid decreasing. Three runs were conducted at different flow rates of 3 L/min, 2 L/min and 1.5 L/m. The resulting heat transfer coefficient increased proportionally with the flow rates with values of 7.1, 6.3, and 5.6 respectively. The overall efficiency of the Plate Heat Exchanger was random as the cold water flow rate was increased. The experiment yielded the highest overall efficiency and best performance when the cold water flow rate was 2 L/min. However, theoretically, the efficiency of the Plate Heat Exchanger should increase with the flow rate. The velocity of fluid flow is significant in regards to heat exchangers. A higher flow rate results in a more turbulent flow, causing more fluid to come in contact with the plate, which will ultimately result in a higher transfer of heat between fluids which was confirmed during this experiment. References ( Khanitha Soeung & Jack Sichantha ) [1] Nourollahi, A. (2024). ME-495 Laboratory Exercise – Number 5 – Heat Plate Exchanger. In ME Dept, SDSU – Nourollahi. SDSU Publishing
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
  • Access to all documents
  • Unlimited textbook solutions
  • 24/7 expert homework help
12 [2] Nourollahi, A. (2024). ME-495 Course Introduction_and Syllabus Spring 2024-1. In ME Dept, SDSU – Nourollahi. SDSU Publishing Appendix ( Khanitha Soeung )
13
14
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
  • Access to all documents
  • Unlimited textbook solutions
  • 24/7 expert homework help