ISSN Online: 2377-424X
ISBN CD: 1-56700-226-9
ISBN Online: 1-56700-225-0
International Heat Transfer Conference 13
EFFECTS OF AXIAL WALL CONDUCTION AND END WALL BOUNDARY CONDITIONS ON THE PERFORMANCE OF TWO-FLUID HEAT EXCHANGERS
摘要
Several, seemingly contradictory conclusions about the effect of axial wall conduction on the performance of two-fluid heat exchangers have been presented in the literature. To investigate this issue further, a simple, one-dimensional, nondimensional, analytical model of a two-fluid heat exchanger is developed. General boundary conditions are applied to the heat exchanger wall at the inlet and outlet. The performance is evaluated using temperature effectiveness expressions defined for each of the two fluid streams. Results show that depending upon the specific temperature effectiveness expression, axial wall conduction may improve or deteriorate the performance of two-fluid heat exchangers. Further, the temperature effectiveness of these heat exchangers may lie outside the traditional 0-1 range. Therefore, new expressions are needed to evaluate the true effectiveness of this class of heat exchangers.