Optimization of diagnostic method for liquid film dynamics in spray cooling and heat transfer characteristics analysis
The liquid film serves as the primary medium directly involved in the spray cooling process and capturing its flow characteristics are crucial.However,accurately capturing these characteristics is extremely challenging due to strong interference from the interaction between droplets,liquid film,and heated wall.As a result,the spray cooling and high-efficiency heat exchange mechanism has not yet been essentially clarified.In this study,we investigated the imaging quality of HFE-7000 and HFE-7100 liquid films to establish an appropriate testing and diagnostic approach for the liquid film dynamics,including the coupled factors such as built-in sensitivity parameters of cameras,shutter speed and aperture combinations,and sampling strategies.The method yielded favorable results for various surfaces.The ADD-type error analyses based on standard liquid films was proposed to determine the bias and random errors associated with relevant parameters.The morphologies,wetted area,and contact line length of HFE-7100 spray under different heat fluxes,pressures,and nozzle heights were obtained to explore the mechanisms governing spray cooling.It was observed that the isolated wetted areas decreased with the increasing surface temperature while the contact lines exhibited either a decreasing or occasionally an increasing trend under certain operating conditions.Furthermore,the connection between liquid film dynamics and heat transfer characteristics was discussed and verified.
spray coolingliquid film flowisolated liquid filmerror analysesHFE-7100
万方数据
维普
