The Experts below are selected from a list of 51 Experts worldwide ranked by ideXlab platform
Wenquan Zhang - One of the best experts on this subject based on the ideXlab platform.
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effect of fuel temperature on cavitation flow inside vertical multi hole Nozzles and spray characteristics with different Nozzle geometries
Experimental Thermal and Fluid Science, 2018Co-Authors: Xin Zhang, Zhixia He, Qian Wang, Zhen Zhou, Wenquan ZhangAbstract:Abstract The effects of the fuel temperature on diesel Nozzle internal flow and the subsequent atomization were analyzed experimentally. Flow visualization was studied using a 10-times scaled-up transparent acrylic model Nozzle with different geometries. A high-speed digital camera was used to capture the flow pattern in the region of the sac chamber and the Nozzle. The energy loss in the occurrence of the hydraulic flip was also analyzed. In addition, cavitation images obtained in the multi-hole Tapered Nozzle with different fuel temperatures had revealed that although the conical shape of the converging Tapered holes suppresses formation of geometry-induced cavitation, string cavitation has been clearly observed anyway. Afterward, the experimental method was used to analyze the effects of the Nozzle sac volume structure on the cavitation flow inside the Nozzle and subsequent spray. It was found that the in-Nozzle flow stage and spray formation were sensitive to the fuel temperature. The visual experiment is helpful to understand the Nozzle flow and optimize the diesel injectors eventually.
Xin Zhang - One of the best experts on this subject based on the ideXlab platform.
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effect of fuel temperature on cavitation flow inside vertical multi hole Nozzles and spray characteristics with different Nozzle geometries
Experimental Thermal and Fluid Science, 2018Co-Authors: Xin Zhang, Zhixia He, Qian Wang, Zhen Zhou, Wenquan ZhangAbstract:Abstract The effects of the fuel temperature on diesel Nozzle internal flow and the subsequent atomization were analyzed experimentally. Flow visualization was studied using a 10-times scaled-up transparent acrylic model Nozzle with different geometries. A high-speed digital camera was used to capture the flow pattern in the region of the sac chamber and the Nozzle. The energy loss in the occurrence of the hydraulic flip was also analyzed. In addition, cavitation images obtained in the multi-hole Tapered Nozzle with different fuel temperatures had revealed that although the conical shape of the converging Tapered holes suppresses formation of geometry-induced cavitation, string cavitation has been clearly observed anyway. Afterward, the experimental method was used to analyze the effects of the Nozzle sac volume structure on the cavitation flow inside the Nozzle and subsequent spray. It was found that the in-Nozzle flow stage and spray formation were sensitive to the fuel temperature. The visual experiment is helpful to understand the Nozzle flow and optimize the diesel injectors eventually.
Seoksu Moon - One of the best experts on this subject based on the ideXlab platform.
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the gasoline atomization characteristics and static pressure distribution of Tapered Nozzle swirl spray
Transactions of The Korean Society of Mechanical Engineers B, 2007Co-Authors: Seoksu Moon, Jaejoon ChoiAbstract:The static pressure distribution, atomization characteristics and velocity distribution of Tapered Nozzle swirl spray is analyzed and then compared with original swirl spray. The static pressure distribution inside the swirl spray is measured using a piezoresistive pressure transducer. Phase Doppler anemometry (PDA) is applied to measure and analyze the droplet size and velocity distribution of Tapered Nozzle and original swirl spray. The static pressure inside the spray shows the lower value compared to the atmospheric pressure and this pressure drop is getting attenuated as the taper angle is increased. The droplet size of Tapered Nozzle spray shows similar value compared to the original swirl spray at the horizontal mainstream while it shows increased value at vertical mainstream. The deteriorated atomization characteristics of Tapered Nozzle spray is improved by applying high fuel temperature injection without causing the spray collapse. The velocity results show that the larger portion of fuel is positioned with higher injection velocity, and the smaller portion of fuel is positioned with lower injection velocity with causing spatially non-uniform mixture distribution.
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paper id iclass 06 113 static pressure distribution inside the swirl spray
2006Co-Authors: Seoksu Moon, Essam Aboserie, Hyun Dong ShinAbstract:The transient static pressure of the air located along the centerline of the spray from a DISI pressure swirl injector was measured for different injection pressures, fuel temperatures and injection durations. The drop in the pressure at the centerline was found to be mainly attributed to the swirling liquid and enhanced with the swirling velocity manifested by the injection pressure. With increasing the injection duration, the pressure was found to be continuously dropped, although the measured swirling momentum of the liquid reaches an asymptotic value and remains constant until the needle starts to close. This implies that the pressure at the centerline of a transient spray does not reach its asymptotic value which corresponds to the case of a continuously injected spray. At higher fuel temperature, the air pressure at the centerline increases and can reach a value more than atmospheric pressure due to the sudden evaporation of the fuel after been released underneath the needle. This high air pressure pushes the main stream of the spray to the radial direction resulting in a larger Nozzle spray angle which is soon collapsed after a short distance due to the severe expansion of the air and enhanced swirling motion. The link between the pressure drop across the spray and liquid film profile for different operating conditions was presented using a simple analytical model. The injector was then modified to eliminate the pressure drop at the center line to have a robust spray that has limited variation with the operating condition and can be used in spray guided gasoline direct injection system. By cutting the Nozzle to have a Tapered Nozzle with an angle less than the flow angle the opened hollow cone shape along the spray streamlines was formed. This shape assists in equalizing the pressure between the centerline and outer part of spray envelop. The results showed that there is a potential from Tapered Nozzle spray to be independent of the operating conditions without much sacrifice of the atomization quality.
J. Q. Feng - One of the best experts on this subject based on the ideXlab platform.
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A Computational Study of Particle Deposition Patterns from a Circular Laminar Jet
Isfahan University of Technology, 2017Co-Authors: J. Q. FengAbstract:To gain insights into ink material deposition behavior during Aerosol Jet® printing, particle deposition patterns on the plate of inertial impactor with circular laminar jet are investigated numerically with a lagrangian solver implemented within the framework of the OpenFOAM® CFD package. Effects of taper angle of the Nozzle channel and jet-to-plate distance are evaluated. The results show quite different particle deposition patterns between Tapered Nozzle and straight Nozzle. At jet Reynolds number Re = 1132, a Tapered Nozzle deposits particles to form a pattern with a high density ring toward the deposition spot edge, especially when the particle Stokes number St > St50, which is absent with a straight Nozzle. Increasing the jet-to-plate distance tends to reduce such particle density peak. Reducing Re to 283 yields particle deposition patterns without the high density ring near the spot edge, with the same Tapered Nozzle. The particle deposition patterns with the straight Nozzle at Re = 283 exhibit further reduced particle density around the spot edge such that the particle density profile appears more like a Gaussian function. In general, the effect of reducing Re on particle deposition pattern seems to be similar to increasing the jet-to-plate distance. The computed particle deposition efficiency η shows the fact that those particles around the jet axis, even with very small values of St, always impact the center of plate, as indicated by the nonvanishing value of η with substantial reduction of St. Such a “small particle contamination” typically amounts to ~10% of small particles (with < 0.1) at Re ~ 1000 and ~5% at Re ~ 300, which may not be negligible in data analysis with inertial impactor measurement
Jaejoon Choi - One of the best experts on this subject based on the ideXlab platform.
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the gasoline atomization characteristics and static pressure distribution of Tapered Nozzle swirl spray
Transactions of The Korean Society of Mechanical Engineers B, 2007Co-Authors: Seoksu Moon, Jaejoon ChoiAbstract:The static pressure distribution, atomization characteristics and velocity distribution of Tapered Nozzle swirl spray is analyzed and then compared with original swirl spray. The static pressure distribution inside the swirl spray is measured using a piezoresistive pressure transducer. Phase Doppler anemometry (PDA) is applied to measure and analyze the droplet size and velocity distribution of Tapered Nozzle and original swirl spray. The static pressure inside the spray shows the lower value compared to the atmospheric pressure and this pressure drop is getting attenuated as the taper angle is increased. The droplet size of Tapered Nozzle spray shows similar value compared to the original swirl spray at the horizontal mainstream while it shows increased value at vertical mainstream. The deteriorated atomization characteristics of Tapered Nozzle spray is improved by applying high fuel temperature injection without causing the spray collapse. The velocity results show that the larger portion of fuel is positioned with higher injection velocity, and the smaller portion of fuel is positioned with lower injection velocity with causing spatially non-uniform mixture distribution.
