Control of Multi-Pass Heat Exchangers : Part 1, Dynamic Characteristics of Two-Pass Heat Exchangers

抄録

The author analyzed 1-2, 3, 4, ……, 2n, 2n+1 pass heat exchangers dynamically. This paper Part 1 contains the exact analysis of two-pass heat exchangers which have one shell-pass and two tube-passes. The author obtained fundamental heat exchange equations. System parameters are combined and arranged in dimensionless forms, and for the typical combinations of these system parameters the transfer functions are obtained. The author found 3rd order characteristic equations governing the heat exchange processes. The equations have coefficients of complex number, and can be solved graphically and numerically. An example of frequency response is given and compared with simple parallel-and counterflow heat exchanger in equal flow conditions. The diagrams show the great difference between the response of this two-pass type and the response of ordinary parallel-and counterflow type, and even in the same two-pass type extraordinary differences are noticed between case P-C and C-P ; especially the input and output relations are important.