HEAT AND MASS TRANSFER IN EVAPORATIVE TUBULAR HEAT EXCHANGER

Abstract

An experimental investigation of heat and mass transfer in evaporative tubular heat exchanger has been conducted, Three arrangements of test unit were employed, viz, a single tube, row of ten tubes in a vertical plane and a 10x10 tube •coi1.12.76 mm 0,D. copper tube was used whose active lengths were 0.683 m, 6.703 m and 66,56 m respectively. Each of the unit was installed in the test section at a time, Heat load was provided by passing hot water as process fluid through the test unit, The air or cooling water or air and water together were passed over the test unit as the cooling fluid to cause heat transfer with only air flow, heat transfer with only water flow and simultaneous heat and mass transfer with air and water flow respectively, Thermocouples were installed to measure the temperatures of the test unit wall, process fluid and cooling water at several locations of the test unit, The heat and mans transfer behaviour was investigated as a function of Reynolds numbers of process fluid, cooling water and air and a newly defined dimensionless enthalpy potential. The latter parameter is the ratio of enthalpy difference of saturated air at tube surface temperature and air flowing over the test unit and the latent heat of vapourisation of cooling water..