Evaporation Heat Transfer of Falling Films on Horizontal Tube. 1st Report, Analytical Study.

Inlet Temperature Effects on Sensible Heat Transfer to Falling Liquid Films on Horizontal Round Tubes

The horizontal-tube, falling film heat exchanger has advantages over flooded bundles and finds widely use in vaporcompression and absorption systems for air-conditioning and refrigeration. The effects of the liquid feeding temperature on inter-tube falling-film heat transfer behavior are investigated experimentally for distilled water, pure ethylene glycol and Dowtherm 4000. It is found that th...

In Tube Evaporation Heat Transfer of Refrigerant Mixtures

Heat transfer coefficient data was taken during in-tube evaporation of five differenct refrigerant mixtures. These measurements were performed in a 318" O.D. (9.7 mm) smooth copper tube at refrigerant temperatures of -zoe and 4°C. Four different mass fluxes ranging from 125 to 375 kg/s-m2 were tested. On a mass basis, the five different mixtures tested were: R-125 (40%) I R-32 (60%), R-32 (30%)...

Experimental Investigation on Evaporation Heat Transfer and Pressure Drop Characteristics of HFC-161 in a Horizontal Smooth Tube

The evaporation heat transfer and pressure drop characteristics of HFC-161 in a horizontal smooth tube with an inside diameter of 9 mm was experimentally investigated. The local heat transfer coefficient and total pressure drop were measured at the heat flux ranging from 15 – 25 kW/m, the mass flux ranging from 100 – 200 kg/(m·s), and the evaporation temperature of 5, 10 °C. The experimental re...

Dominant Flow Mechanisms in Falling-Film and Droplet Mode Evaporation Over Horizontal Rectangular Tube Banks

Flow visualization with high-speed video of evaporating water films falling over flat horizontal tubes, representative of the external surfaces of microchannel tubes, is presented. Experiments were conducted with 1.4 mm thick and 27 mm tall tubes over a film Reynolds number range of 23 < Re < 126. In addition to a qualitative description of the flow mechanisms, this work quantifies key droplet ...

Saturated Flow Boiling Heat Transfer in Horizontal Square Tube