A numerical study of heat transfer processes in heat exchangers with diffuser channels with liquid coolants was carried out. Plate heat exchangers with channel expansion angles within a few degrees, which do not lead to separation of the flow from the wall, are considered. Due to the increase in heat exchange intensity in expanding channels, the heat transfer power with increasing expansion angle increases in comparison with heat exchangers with a constant channel cross-section. It is shown that when water is used as a «cold» coolant, the heat transfer power increases with increasing Prandtl number of «hot» coolants, which were mercury, water and transformer oil. The calculations used a three-parameter RANS model of turbulence, supplemented with a transport equation for turbulent heat flow.
heat exchanger, diffuser channel, RANS turbulence model
Пластинчатый теплообменник с диффузорными каналами с жидкими теплоносителями
Проведено численное исследование теплообменных процессов в теплообменниках с диффузорными каналами с жидкими теплоносителями. Рассмотрены пластинчатые теп-лообменники с углами расширения каналов в пределах нескольких градусов, не приво-дящими к отрыву потока от стенки. Показано, что за счет увеличения интенсивности теплообмена в расширяющихся каналах мощность теплопередачи с ростом угла расши-рения возрастает в сравнении с теплообменниками с постоянным сечением каналов. При использовании воды в качестве «холодного» теплоносителя мощность теплопередачи возрастает с ростом значения числа Прандтля «горячих» теплоносителей, в качестве которых рассматривались ртуть, вода и трансформаторное масло. Расчеты проводились с использованием трехпараметрической RANS-модели турбулентности, дополненной транспортным уравнением для турбулентного теплового потока.
течение с теплообменом, плоский диффузор, RANS-модель турбулентности
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