THERMAL EFFICIENCY ANALYSIS OF CROSS-FINNED TUBES

Finned heat exchangers are the basic type of heat exchanger employed in many industrial applications such as refrigeration, air conditioning and other thermal processes. This paper presents experimental research of air-side heat transfer of finned surfaces. Seven types of finned surfaces are employed in this study. Investigation describes temperature fields and temperature cooling air-flow changing in the inter-fin duct without taking into account tube section. Temperature difference in-between local real air temperature data and fin surfaces are determined. The air-side heat transfer coefficients of finned tubes were evaluated at various air flow rate. Experimental setup was designed to simulate a single passage in a fin-tube heat exchanger. The heat transfer improvement of finned surfaces is a problem which includes several factors. Among the main factors are the fin form and its material. A series of tests presented in this paper reveal visual and quantitative details of local fin-surface temperature distributions for steel and aluminum fins. The air-side thermal performance data of finned surfaces were analyzed using conditional coefficient of heat transfer. Tube displacement in regard to fin on its thermal characteristics is evaluated. Experimental results have also shown that edge type of the inter-fin duct is not influenced on heat exchange performance. The results of research indicate that conditional coefficient of heat transfer can be used for performance comparison of finned heat exchange surfaces. This method is very useful for simple heat transfer estimation of finned surfaces for a wide range of practical applications.