PULSATING HEAT TRANSFER INTENSIFICATION IN A PLATE HEAT EXCHANGER
The article is devoted to the effect of pulsating coolant supply on heat transfer. The analysis of foreign literary sources does not give an unambiguous answer to this question. The results of experiments and mathematical modeling obtained by various authors can be divided into three categories, i.e. heat transfer enhancement; weakening of heat transfer; does not affect heat transfer. The presented data of the results of experiments conducted by the authors of this article indicate that, in the frequency range 0.45 and 2.23 Hz, the pulsating flow of the heat carrier allows one to intensify the heat transfer in the plate heat exchanger at the Reynolds numbers of the pulsating flow (calculated from the average flow rate) from 1800 to 9000 A shock valve is used as a device for creating pulsations, instantly blocking the flow of coolant. A relative increase in the heat transfer coefficient in the pulsed mode (in comparison with the stationary one) with equal costs up to 13?% is obtained. At all costs, the maximums of the experimental graphs are observed in the frequency domain 1.78 Hz. Starting from this frequency, the heat transfer coefficient decreases with a constant flow of heated and heating media. The Reynolds number in the experiments varied from 1800 to 9000, the Prandtl number from 5.2 to 5.6.