DEVELOPMENT OF EXTENDED SURFACE HEAT TRANSFER EQUIPMENT AS LABORATORIES TEACHING AIDS

Abstract

One of the effective ways of enhancing the heat transfer rate between a solid and an adjoining fluid is through the use of an extended surface called fin. Extended surface enhances the heat transfer rate by increasing the area of the surface through which heat is transferred. This paper presents the design, construction and testing of an extended surface heat transfer teaching equipment. Extended heat transfer equipment is made of metal rod of 10 mm diameter and length 350 mm, heater of 60 W capacity, Plaster of Paris (P.O.P) insulator, stands-support for heater, insulator and the metal rod and base flat bed of 500 mm × 200 mm × 80 mm.  Experimental studies were carried out on three materials (brass, mild steel and aluminum) to determine their respective temperature distribution along an extended surface over a length of 28 cm for 2700 seconds interval at different voltage of 50, 100 and 150 volts. The theoretical analysis results were compared with the experimental results and the temperature distribution in the three materials were compared. The results revealed that, Aluminium has the highest temperature value, followed by Brass and Mild Steel at different voltages considered. The temperature increases as voltage increases, at 50, 100 and 150 volts, temperature values are 70, 113 and 157 ^oC for Aluminum, 65, 111 and 141 ^oC for Brass and 60, 87 and 100 ^oC for Mild Steel respectively for 2700 seconds. This explains the reason why Aluminium has the highest heat transfer characteristics followed by Brass and Mild steel. Statistical t-test analysis at 95% confidence limit confirmed that there is no significant difference between the theoretical results and experimental results. Analysis of variance, ANOVA at 95% confidence limit confirmed that, there is significant difference between the temperature gradient of the three selected material. Finally, the extended surface heat transfer equipment is affordable as produced with locally available materials; It has enhance easy maintenance, reliability and accuracy of results. It can be used as teaching aids in laboratories and research institutes.