Pool Boiling Heat Transfer Characteristics of R-134a in Titanium Horizontal Plain and Low Finned Tubes

Pool boiling heat transfer characteristics of R-134a were investigated in titanium plain and low finned tubes. The diameter of test tube was 15.88 mm and the fin density was 33 fpi. Tests were conducted at saturation temperatures of 20 degrees C and 30 degrees C. Heat fluxes varied from 5000 W/m(2) to 50,000 W/m(2) based on surface area of the plain tube. The pool boiling heat transfer coefficients of the titanium horizontal plain tube are lower than those of the copper plain tube by 8.2%. The boiling heat transfer coefficients of the low finned tube are averagely higher than those of the plain tubes by 34%. The average deviation of the Slipcevic correlation from the present data for the low finned tube is 20%.