The Effect of Unsteadiness of Gas Flow in the Matrix Channel of a Rotating Heat Exchanger on its Thermal Parameters during Laminar Flow

The influence of unsteadiness of the gas flow in the channel of the slot matrix of a rotating heat exchanger on its thermal characteristics is studied. For this purpose, mathematical simulation of conjugate heat transfer during the flow of air along the steel walls forming the analyzed channel is carried out. Due to the features of the rotating heat exchanger’s operation, mathematical simulation is carried out repeatedly using the results obtained as initial conditions for the following calculations to obtain the parameters of conjugate heat transfer in the nominal mode. It is shown that the flow in the studied channel of the matrix of the heat exchanger repeats itself every 60 cycles. The distribution curves of the local values of the Nusselt criterion along the length of the channel at all timesteps of the flow process, as well as the values of the Nusselt criterion averaged over the length of the channel, are calculated. It is shown that the average value of the Nusselt criterion increases gradually over time. The time-averaged value of the Nusselt criterion is determined and is shown to slightly exceed the values obtained in the steady formulation.