Cooling of Superheated Refrigerants Flowing Inside Mini and Micro Tubes, Study of Heat Transfer and Pressure Drop, CO2 Case Study

Superheated Carbon dioxide gas was subjected to a cooling process. Experimental investigation along with an analytical study was carried out in this work. This work is intended to be part of the super critical Gustav Lorentzen refrigeration cycle of CO2. Experimental and analytical works concentrated on heat transfer and pressure drop for single phase flow during gas cooling inside mini and micro tubes. Empirical correlations were formulated analytically for the coefficient of convectional heat transfer and for the pressure drop in the following forms:Nu = 0.24 (Re)^0.53 (Pr)^0.43 And Eu = 1.1*10^-4 (ReD)^-0.26 (L/D)^1.06 Correlations were validated against some experimental results and compared to all experimental results and other literature correlations; an agreement of more than 90% was noticed. This work can enhance the calculations of heat flux and pressure drop of gases flow inside mini and micro tubes. It can also help in the design procedure of heat exchangers and cooling processes