The Statistical Analysis of Droplet Train Splashing After Impinging on a Superheated Surface

An orderly droplet splashing is established when a water droplet train impinges onto a superheated copper surface. The droplets continuously impinge onto the surface with a rate of 40,000 Hz, a diameter of 96 μm or 120 μm, and a velocity of 8.4 m/s or 14.5 m/s. The heat transfers under different wall temperatures are measured, and the corresponding droplet splashing is recorded and analyzed. The effects of wall temperature, droplet Weber number, and surface roughness on the transition of the droplet splashing are investigated. The results suggest that the transferred energy is kept a constant in the transition regime, but a sudden drop of around 25% is observed when it steps into post-transition regime, indicating that the Leidenfrost point is reached. A higher Weber number of droplet train results in a more stable splashing angle and a wider range of splashed droplet diameter. The surface roughness plays no significant role in influencing the splashing angle in the high Weber number case, but the rougher surface elevates the fluctuation of the splashing angle in the low Weber number case. On the rougher surface, the temporary accumulation of the impact droplets is observed, a “huge” secondary droplet can be formed and released. The continuous generation of the huge droplets is observed at a higher wall temperature. Based on the result of droplet tracking of the splashed secondary droplets, the diameter and velocity are correlated.

The Experimental Study on Effects of Height and Hold up on performance of Vertical Gas-Liquid Separator using Amin Contactor Tower

In present research, first the treatment of flow in designed vertical gas-liquid separator and Amin contactor tower at refinery in order to reduce of liquid percent was simulated. In order to simulation was used three dimension model with finite volume method numerically. Then separator and contactor tower has been modeled three dimensional and for droplet tracking in continuous phase has been used discrete phase model (DPM) with turbulence RNG k-Ɛ model. Also the gambit software is used for three dimension designs and fluent is used for solution governing equations of flow field. After simulation, the governing model of separator and contactor tower, fluid flow, the effect of growing of liquid droplet, droplet settling length (disengagement time) was studied. After analysis and compare behavior of flow in separator and tower, the results of simulation compared with experimental results at sweetening unit in Sarkhoun and Qeshm gas treating company that has 95% compatibility. The simulation results has shown that TOTAL method has more compatibility with relation to other methods so that one of effective parameters in improvement of separation process is growing of liquid droplets and separation factor depend on that, also more disengagement time causes increase hold up time and finally growing of liquid droplets. Additionally according to younger's comment gas-liquid separators can applied in horizontal or vertical status so that he founded if L/D be 1.7 to 3.6, the separators should be used vertically also Branan has proved that if L/D > 5, a horizontal separator should be used. The results of research are shown that in special conditions with L/D>6.5 can apply vertical separator. Finally experimental data has shown that the settling length can be 36 ft (11m) that separation works well and according to Schiman this length should be 0.75D or a minimum 12in (0.305 m) whereas Gerunda recommends a length equal to the diameter or a minimum of 3 ft (0.914 m) that present result is new recommendation.