Experimental Study On The Liquid Distributor And Heat-Trasfer Performance Of Horizontal Tube Falling Film Evaporator

Since there are many advantages for the horizontal-tube falling film evaporation technologies, such as higher evaporation intensity, lower temperature, higher heat-transfer coefficient, more excellent performance at low temperature. This technology has been applied in various fields as desalinization of sea-water, electricity generation by temperature interval of ocean, cooling engineer and chemical engineering and so on. Liquid distribution and evaporation heat-transfer performance were studied in this paper by theoretical analysis and experimental research.The ladder liquid distributor was designed for the horizontal falling film evaporation. The liquid distributor was fixed at the bottom of the flow pipe, and there was a water-spreading device at the bottom side of the fist floor heat-transfer pipes, it was easy for design and manufacture, a method was provided for liquid adequate distribution. The flow formulas and revised momentum equation were given from the analysis of flow performance in porous pipe manifolds, the design proposal and the statistic concept of calculating the distributive unwell-distributed coefficient was put forward, a new experimental device was constructed to test the performance of the distributor.Effect of evaporation and heat transfer efficiency of this type of evaporator were compared with different liquid spraying rate, heat flux, and evaporation temperature. The result showed that when 0.0 ,the film coefficient of heat-transfer was 2 kg / m ? s≤Γ≤0.16 kg /m ?sdecreased first then increased, when heat flux was between and 112.5 , 92.5 kW /m 2kW /m2the film coefficient of heat-transfer was increased along with the accretion of heat flux, and the film coefficient of heat-transfer was increased along with accretion of evaporation temperature. The heat-transfer coefficient of tube bundle was increased first then decreased with the liquid spraying rate increasing, increased along with accretion of heat flux, increased along with accretion of evaporation temperature. A model of laminar flow was established from fluid mechanics principle and evaporation heat transfer theory, the equation of liquid film thickness at any angle, and the zero dimension heat transfer coefficient correlation formula was educed.