DETERMINATION OF HEAT TRANSFER COEFFICIENTS OF BOILING REFRIGERANTS PERTINENT TO THE COLD ACCUMULATORS’ CONDITIONS

The use of correlations that would be capable to adequately account for the heat transfer between the surface and refrigerant are crucial for the accurate design calculations and proper heat transfer equipment sizing, including cold accumulators with ice generation on the heat transfer surface. A vast multitude of such correlations for the determination of overall heat transfer coefficient valid for different cross sections pipes and processes conditions are available now in the literature. The calculations of heat transfer pertinent to the conditions of cold accumulators, lead to the results drastically deviating from those obtained in the framework of the direct experimentation carried out at the Department of Power Engineering and Industrial Refrigeration of NUFT. In order to mark one or some of such correlations, that might have been used within the engineering calculations under condition of their proper correction, the critical comparative analysis of the literature sources has been carried out. The mathematical modeling of the heat transfer process in the condition of boiling refrigerant, with taking into account the valid limitations towards correlations, has been performed. The graphical comparison of the modeling results calculation with chosen correlations is performed. The results of the analysis allowed choosing the correlations, which could be recommended to be used within the engineering design calculations of cold accumulators with the ice accumulation on the heat transfer surface. The applications of such design correlations that adequately reflect the mechanism of heat transfer between the surface and refrigerant would be critical for the accurate design calculations of the transfer equipment of the refrigeration units, including cold accumulators with ice generation.