Dynamic Behaviour Of Heat Exchangers
Free (open access)
W Roetzel, M Li & X Luo
Although a lot of models for modeling and simulation of dynamic behaviour of heat exchangers were suggested, they were only for specified types of heat exchangers. In the present investigation a general model for dynamic analysis of one-dimensional flow heat exchangers is developed. Dynamic responses to arbitrary temperature transients belong to linear problems and can be solved exactly. For small disturbances in thermal flow rates, heat transfer coefficients or flow distribution factors a linearized model is developed. The solutions are obtained by means of Laplace transform and FFT (fast Fourier transform) inverse technique. By introducing the matching matrices, the above solutions become general and can be applied not only to multistream multipass shell-and-tube heat exchangers and plate heat exchangers but also to their networks. The time delays in connecting pipes are included in the models. Based on the analytical and numerical analyses the dynamic parameters of heat exchangers used for automatic control of systems are evaluated.