Enhancement of heat transfer of heat exchangers using in transport by pulsating flow

Abstract

The oil coolers are used in the hydraulic system of transport vehicles. In the shell and tube water oil coolers, oil is can be located on the tube side, water in the shell side. Different enhancement of heat transfer methods is used in oil coolers. The paper presents the results of a numerical study of the effect of asymmetric flow pulsations on the enhancement of heat transfer in a pipe for a highly viscous fluid with a Prandtl number Pr 293. The pipe length was 12 pipe diameters. The Reynolds number Re calculated from the inner diameter of the pipe was 100. The Strouhal number Sh was inside the range from 0.14 to 1.13. The amplitude of the pulsations of the flow had a reciprocating motion. The dimensionless relative amplitude of the pulsations was 1, 3, and 5. An increase in heat transfer was observed over the entire range of pulsation frequencies and amplitudes. The intensity of the pulsating flow significantly increases the heat transfer in the pipe. A comparison of the effectiveness of harmonical and asymmetric pulsations for enhancement of heat transfer was carried out. It is noted that the efficiency of asymmetric pulsations increases with increasing amplitude and frequency of pulsations. The maximum enhancement of heat transfer with asymmetric and harmonic pulsations was 2.03 and 1.93, respectively.