Evaporation of liquid ammonia distributed by commercial spray nozzles onto a horizontal low-fin steel tube of 3/4 in. diameter was tested. Experiments were conducted for the average local spray flow rate from 0.0139 kg/(s•m) to 0.0788 kg/(s•m), saturation temperature from -23.3°C to 10°C, and heat flux from 10 kW/m2 to 80 kW/m2. The effects of heat flux, saturation temperature, spray flow rate, and nozzle height were investigated. Both standard-angle and wide-angle commercial nozzles were tested. The Nu data were correlated as a function of Re, Pr, reduced pressure, and heat flux. The heat transfer coefficient data of the low-fin tube are compared with those of a corrugated tube and plain tube.

Units: SI