Buoyancy driven flow in counter flow heat exchangers

Abstract

The temperature distribution, the buoyancy head and the flow rate have been studied in a counter flow heat exchanger having buoyancy driven flow on at least one side. The assumptions made for heat flux distribution are varied and the resulting effects on the flow rate and fluid temperatures are studied. A network model is used to simulate the temperature distribution and oil flow rates in an oil-filled power transformer cooled by radiators. It is found that for operating conditions normally found for mineral oil the counter flow assumptions for heat flux distribution gives approximately the same results as assuming uniform heat flux. When a more viscous oil type is used or the radiators are placed lower than normal relative to the heat generating parts, the counter flow assumptions give more reliable results. © Published under licence by IOP Publishing Ltd.