Experimental Investigation of evaporation of propane (R290) in small pipes
MetadataVis full innførsel
This master thesis discusses the two-phase boiling pressure drop and heat transfer characteristics of propane in different test conditions in an experimental setup. One smooth tube with inside diameter of Di=4.2 mm was used. Saturation temperatures of °0,°5,°10C were tested. Mass flux ranged from G=250-505 Kg/(m^2 s) , heat flux was adjusted to be equal to a vapor fraction increase ranging Δx=0.1-0.4, this is corresponding to a heat flux of q=15-62 Kw/m^2 , length of test section was equal to 0.5m. Current literature has been reviewed to make an overall view of current knowledge combined with a smaller number of studies investigating other new forms of refrigerants and subjects of interest. Several existing pressure drop and heat transfer coefficient prediction methods were reviewed. Prior tests were categorized based on the inlet diameter of tube, tube material and surface finish, saturation temperature, mass flux, heat flux and the heating medium provided. Results show an increase of heat transfer coefficient with increased mass flux and heat flux and vapor quality before dry out; as for pressure drop, it sees an increase with increasing heat and mass flux and whereas there is also an increase with increasing vapor fraction; this trend is reversed for high vapor qualities. Correlation of (Sun & Mishima, 2008) was found to be reliable for prediction of pressure drop, none of the correlations for heat transfer coefficient were reliable with correlation of (Shah, 1982) having the least MRD of 100%.