The effect of an inline row of tube bundles on heat transfer in a pulsating flow

Increasing the efficiency of heat exchange equipment is closely related to different methods of intensefying heat transfer. One such method is forced flow pulsation. Pulsating flows in tube bundles are limited to single operations. Using a numerical method, this article considers the position of the cylinder in a tube bundle on its heat transfer in a pulsating flow. The numerical experiment was carried out under two-dimensional flow conditions, with a longitudinal and transverse relative pitch of 1.4. The number of tubes in the longitudinal direction was seven. The Reynolds number corresponded to 1500, while the thermophysical properties of the working medium were assumed constant and corresponded to the Prandtl number 4.03. Calculations were carried out in Ansys Fluent for stationary and pulsating flows. The forced flow pulsations had an asymmetrical reciprocating character. The pulsation amplitude relative to the cylinder diameter had values of 0.1, 0.2, 0.3, and 0.4; the pulsation frequency corresponded to 0.2, 0.4, 0.6, and 0.8 Hz. The results of the numerical experiment showed that with stationary or pulsating flows, there is an increase in heat transfer along the length of the tube bundle. The maximum increase in heat transfer occurs in the last row. In a pulsating flow, in all studied modes, an intensification of heat transfer is observed for all rows of the tube bundle, while the intensification varies depending on the row and pulsation parameters. The heat transfer of the first row and subsequent rows in a pulsating flow is lower compared to a stationary flow, therefore, the maximum intensification is observed for the first row. The influence of the position of the cylinder along the length of the inline tube bundle decreased with increasing frequency and amplitude of pulsations. The maximum intensification of 1.51 times was observed in the first row at the maximum amplitude and frequency of pulsations.