INEXPENSIVE HEAT TRANSFER EQUIPMENT TO DEMONSTRATE THE EFFECT OF EXTENDED SURFACES ON THE CONVECTION HEAT TRANSFER RATE

摘要

Extended surfaces are used specifically to increase heat transfer rate between a solid and an adjacent fluid. The rate of heat transfer is from the solid surface to the fluid is governed by the Newton's law of cooling. A simple inexpensive apparatus to demonstrate the effect of the length of the extended surface and the effect of different materials on the heat transfer rate was developed with the assistance of senior students enrolled in a senior project. Using this apparatus student was able to determine the temperature gradient and calculate the heat losses to the surroundings assuming infinitely long extended surface or negligible heat loss from the tip of the extended surface. Experiments were performed on three different materials, aluminum, copper and stainless steel by maintaining the base of the fin at a constant temperature and taking temperature measurements at regular intervals along the length of the extended surface. The apparatus was developed to be portable and used in a class room environment to enhance the understanding of heat transfer principles during a lecture rather than in a laboratory situation. The visual communication is much more powerful in many learning situations; the spoken word may be redundant. The feedback from the students was overwhelmingly positive. The paper describes the apparatus, method of construction and experimental results in a graphical form with discussion questions and answers