Part one: Experimental procedure
The experiment to establish the extended surface heat transfer employed the use of two apparatus: Extended surface heat transfer accessory (HT15) and heat transfer service unit (HT10X). The extended surface heat transfer accessory heater was connected to the HT10XC. The thermocouples from the HT15 were then connected to the HT10XC. This was followed by setting the voltage control potentiometer to a minimum. The switch selector was then set to manual. The voltage of the heater was set to 6 V and the measurements were taken afterward. The above steps were repeated for heater voltage of 9 V and 12 V.
Part two: Computational component
The MAE3310_ExtendedSurface.mph was downloaded from Blackboard. After the download was complete, Class kit License COMSOL Multiphysics was opened. The computer cursor was used to navigate to File, Open and then MAE3310_ExtendedSurface.mph was selected. Fin 1 and MAE3310_ExtendedSurface.mph were used to model the experimental set up in the COMSOL file. The Heat Transfer in Solids was expanded to expose the boundary conditions used to simulate the experiment. One end of the fin exposes the applied heat flux which represents the heater while the other end of the fin is regarded as insulated since its butts up against a plastic fitting (Kraus, Abdul and James 34). A thermal insulation condition was applied at the end of the fin. Convective cooling, as well as a surface to ambient radiation conditions, was implemented to the external circumference of the fin. The application of both ambient radiation and convective cooling was used to represent interaction with the room. The set up was then used to examine various parameters such as the fin length, fin diameter, and the fin tip condition. Additionally, the effects of these parameters on the temperature distribution in the fin were examined.
Evaluation 1
Five different fin lengths were examined so as to determine the effects of these dimensions on performance. The following dimensions were evaluated for fin 1 to fin 5: 35,55,75,95 and 15 cm respectively. Since fin 1 had already been examined, it was used as the baseline for evaluating the remaining fins 2, 3, 4 and 5.
A steady-state study was created using the instructions in Appendix 1. Using the Geometry option, fin 1 was disabled while enabling Fin 2 (55 cm) and Build All option was selected. Still under Geometry, after the Build All option was selected, the parameter was placed under Mesh then built using the Build All option. The study was selected, and Compute option pressed to evaluate the parameter of the fin 2. The above steps were repeated for fin 3 4 and 5.
The temperatures along the centerline of the fin were extracted from the data using a cut line positioned along the fin axis. The correct solution was assigned to each line since the cut line had already been generated. The instructions for producing a 3 D cut line was used for Runs 1 to 5.
The data obtained was used to plot the curve of temperature against position for the five different fins. The TemperatureVsPositon-FinLength was expanded under Results. The instructions for producing a 1 D-line graph were used for Runs 1 to 5. The figure was saved to a file by clicking the camera icon. After the first evaluation had been completed, the file was saved as MAE3311_ExtendedSurface_Eval1.
Evaluation 2
Evaluation 2 was used to determine the effect of diameter on fin performance. Fin 1 was set at a diameter of 10mm while fins 6 to 9 were set to; 12.5, 15. 7.5 And 5 mm respectively. The data was used to examine different fin diameters. A steady study was generated using the instructions in Appendix 1. Fin 5 was disabled using the Geometry option, and then Build All was selected. A selection of the following options followed respectively; Mesh and Build All. Study 6 was selected and then computed. The above steps were repeated for Fins 7, 8 and 9.
The temperature data was gathered along the center fin line using a cut line. The instructions for generating a 3D cut line were used for Runs 6 to 9. A plot of temperature versus position was produced for the five different diameter fins. TemperatureVsPosition-Diameter was expanded under Result option. The instruction for generating a 1 D-line graph was used for Runs 1, 6, 7,8 and 9. The figure was saved to a file by clicking on the camera icon. Evaluation 2 was completed, and the file was saved as MAE3311_ExtendedSurface_Eval2.
Evaluation 3
The effect of tip condition on the fin performance was investigated. Fin 1 was examined with an insulated tip condition. A convection tip condition was applied to Fin 10 and a constant temperature tip condition applied to Fin 11, and the results were compared to fin 1. A steady-state study was created. The Geometry option was used to disable fin nine while enabling fin 10. The convection tip condition was set and solved.
The Heat Transfer in Solids was expanded, and Convection Cooling 2 was enabled. The fin tip was selected using the plus sign. A heat transfer coefficient that matches the matches the value used for the convection from the fin perimeter to the environs was inserted. The next step followed the Mesh-Build All procedure. Study 10 was selected so as to compute the entered data.
A steady-state study was created using the instructions available in Appendix 1. Fin 10 was disabled under the Geometry option while Fin 11 was enabled and Build All option was selected. A constant temperature was then set and solved. Convective Cooling 2 was disabled under the Heat Transfer in Solids option. Temperature 1 was enabled under the same option, and the fin tip was selected. A temperature of 300k was entered into the system by clicking the plus sign. The Mesh-Build All Study 11 and compute procedure followed.
The temperature data along the fin centerline was collected using a cut line. The instructions for generating a 3D line were used for Runs 6 to 9. The temperature distribution for the three different fin conditions was plotted. The TemperatureVsPosition-TipCondition was expanded using the Results option. The instructions for generating 1D line graph was used for Runs 1, 10 and 11.The figure was saved to a file by clicking the camera icon. Evaluation 3 was completed, and the file was saved as MAE3311_ExtendedSurface_Eval3.
Works Cited
Kraus, Allan D., Abdul Aziz, and James Welty. Extended surface heat transfer. John Wiley & Sons, 2002.
