Simulation of dynamical response of a countercurrent heat exchanger to inlet temperature or mass flow rate change

This paper simulates the dynamical response of a countercurrent heat exchanger. The model, which is employed for this purpose for the first time, employs the numerical method based on the analytical solution of the energy equation. The details of this method are introduced in the paper. Furthermore, the transient behavior of the system is considered for two cases. In the first case, the system response to the inlet temperature change of both fluids is studied. In the second case, the inlet mass flow rate change and its effect on the system behavior are analyzed. The time constant variation is considered during the dynamical behavior of the system. It was shown that the time constant behaves differently for both of the fluids. Finally, a parametric study on the effect of the mass flow rate on the system response is carried out. Comparison of the present results with the experimental data and analytical results of the other researchers confirms that this model can be used for system response prediction with a high level of confidence. This method has great capability in reducing the mathematical calculation amount and CPU time.