scholarly journals Effects of deflectors in liquid-liquid pintle injector with various momentum ratio

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Ingyu Lee ◽  
Gijeong Jeong ◽  
Youngbin Yoon
Keyword(s):  
Momentum Ratio

Effects of momentum ratio and velocity difference on combustion performance in lignite-fired pulverized boiler

Energy ◽  
2018 ◽  
Vol 165 ◽  
pp. 825-839 ◽  
Author(s):  
Zixiang Li ◽  
Zhengqing Miao ◽  
Xusheng Shen ◽  
Jiangtao Li
Keyword(s):  
Velocity Difference ◽  
Momentum Ratio ◽  
Combustion Performance

Experimental Study of the Endwall Heat Transfer of a Transonic Nozzle Guide Vane With Upstream Jet Purge Cooling: Part 1 — Effect of Density Ratio

2020 ◽  
Author(s):  
Shuo Mao ◽  
Ridge A. Sibold ◽  
Stephen Lash ◽  
Wing F. Ng ◽  
Hongzhou Xu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Mass Flux ◽  
Guide Vane ◽  
Density Ratio ◽  
Momentum Ratio ◽  
Blowing Ratio ◽  
Nozzle Guide Vane ◽  
Nozzle Guide ◽  
The Impact

Abstract Nozzle guide vane platforms often employ complex cooling schemes to mitigate ever-increasing thermal loads on endwall. Understanding the impact of advanced cooling schemes amid the highly complex three-dimensional secondary flow is vital to engine efficiency and durability. This study analyzes and describes the effect of coolant to mainstream blowing ratio, momentum ratio and density ratio for a typical axisymmetric converging nozzle guide vane platform with an upstream doublet staggered, steep-injection, cylindrical hole jet purge cooling scheme. Nominal flow conditions were engine representative and as follows: Maexit = 0.85, Reexit/Cax = 1.5 × 106 and an inlet large-scale freestream turbulence intensity of 16%. Two blowing ratios were investigated, each corresponding to upper and lower engine extrema at M = 3.5 and 2.5, respectively. For each blowing ratio, the coolant to mainstream density ratio was varied between DR = 1.2, representing typical experimental neglect of coolant density, and DR = 1.95, representative of typical engine conditions. An optimal coolant momentum ratio between = 6.3 and 10.2 is identified for in-passage film effectiveness and net heat flux reduction, at which the coolant suppresses and overcomes secondary flows but imparts minimal turbulence and remains attached to endwall. Progression beyond this point leads to cooling effectiveness degradation and increased endwall heat flux. Endwall heat transfer does not scale well with one single parameter; increasing with increasing mass flux for the low density case but decreasing with increasing mass flux of high density coolant. From the results gathered, both coolant to mainstream density ratio and blowing ratio should be considered for accurate testing, analysis and prediction of purge jet cooling scheme performance.

Effect of Momentum Ratio on the Mixing Performance of Unlike Split Triplet Injectors

2002 ◽  
Vol 18 (4) ◽  
pp. 847-854 ◽  
Author(s):  
Y. D. Won ◽  
Y. H. Cho ◽  
S. W. Lee ◽  
W. S. Yoon
Keyword(s):  
Momentum Ratio ◽  
Mixing Performance

scholarly journals Aerodynamic Research on Straight Wall Annular Diffuser for Turbofan Augmentor

1985 ◽  
Author(s):  
Q. M. Xie ◽  
J. G. Gu
Keyword(s):  
Velocity Profile ◽  
Temperature Profile ◽  
Aerodynamic Performance ◽  
Recovery Coefficient ◽  
Momentum Ratio ◽  
Inlet Velocity ◽  
Straight Wall ◽  
Annular Diffuser ◽  
Aerodynamic Test ◽  
Pressure Recovery Coefficient

The effect of non-uniform inlet velocity and temperature profile on the aerodynamic performance of straight wall annular diffuser for turbofan augmentor has been investigated. The distribution of static pressure, stagnation pressure and temperature has been measured, thus pressure recovery coefficient, velocity profile and temperature profile at different axial station along the diffuser center line can be determined. The experimental results showed that the momentum ratio ρ¯eV¯e2/ρ¯iV¯i2 of two streams across the diffuser inlet flow splitter is the non-dimensional flow parameter controlling diffuser aerodynamic performance. Thus, it is possible to simulate turbofan augmentor annular diffuser perfomance by using low temperature air flow aerodynamic test under the condition that the diffusers are of similar geometry, have the same inlet velocity profile and maintain the momentum ratio constant. A correlation for the velocity distribution in the diffuser was also obtained.

Effect of Fuel/Air Ratio on Air Blast Simplex Nozzle Performance

1997 ◽  
Author(s):  
Michael A. Benjamin ◽  
Vincent G. McDonell ◽  
G. Scott Samuelsen
Keyword(s):  
Mechanical Design ◽  
Separated Flow ◽  
Effective Area ◽  
Spray Angle ◽  
Mass Ratio ◽  
Gas Turbine Combustor ◽  
Major Barrier ◽  
Momentum Ratio ◽  
Air Blast ◽  
Air Mass

The Air-Blast Simplex (ABS) nozzle may have significant mechanical design advantages when compared to Pure Air-Blast (PAB) designs, and attractive cost benefits. The major barrier to implementing ABS nozzles is spray collapse at high ambient pressures. The present study addresses this issue, and presents the results in a manner that is useful to the gas turbine combustor designer. The results reveal that spray collapse is not significant as long as the fuel-to-air mass ratio is maintained below about 0.3. The results also reveal two distinct curves for air effective area that are attributed to the presence or lack of flow separation in the vane/shroud assembly. In the case of the separated flow, a larger rate of decrease in effective area with increasing fuel air mass or momentum ratio is observed. These results help address ABS spray angle collapse at high pressure, and identify strategies that may adequately mitigate, or even eliminate, spray collapse in a suitably designed combustor.

Film Cooling Performance of Converging-Slot Holes With Different Exit-Entry Area Ratios

2009 ◽  
Author(s):  
Cun-liang Liu ◽  
Hui-ren Zhu ◽  
Jiang-tao Bai ◽  
Du-chun Xu
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Film Cooling ◽  
Thermal Protection ◽  
Area Ratio ◽  
Cooling Effectiveness ◽  
Momentum Ratio ◽  
Film Cooling Effectiveness ◽  
Distribution Features

Film cooling performances of two kinds of converging slot-hole (console) with different exit-entry area ratios have been measured using a new transient liquid crystal measurement technique which can process the nonuniform initial wall temperature. Four momentum ratios are tested. The film cooling effectiveness distribution features are similar for the two consoles under all the momentum ratios. Consoles with smaller exit-entry area ratio produce higher cooling effectiveness. And the laterally averaged cooling effectiveness results show that the best momentum ratio for both consoles’ film cooling effectiveness distribution is around 2. For both consoles, the heat transfer in the midspan region is stronger than that in the hole centerline region in the upstream, but gradually becomes weaker as flowing downstream. With the momentum ratio increasing, the normalized heat transfer coefficient h/ho of both consoles increases. In the upstream, heat transfer coefficient of console with small exit-entry area ratio is higher. But in the downstream, the jets’ turbulence and the couple vortices play notable elevating effect on the heat transfer coefficient for large exit-entry area ratio case, especially under small momentum ratios. Consoles with smaller exit-entry area ratio provide better thermal protection because of higher cooling effectiveness. And the distributions of heat flux ratio are similar with those of cooling effectiveness because the influence of η on q/q0 is larger. For the consoles, smaller exit-entry area ratios produce lower discharge coefficients when the pressure variation caused by the hole shaped is regarded as flow resistant.

scholarly journals Influence of momentum ratio and its throttling method on spray characteristics of pintle injector

2019 ◽  
Vol 68 (20) ◽  
pp. 204704
Author(s):  
Hui-Yuan Chen ◽  
Qing-Lian Li ◽  
Peng Cheng ◽  
Wen-Hao Lin ◽  
Chen-Yang Li
Keyword(s):  
Spray Characteristics ◽  
Momentum Ratio

A Stochastic Immersed Model of Breakup Characteristics in Dense Air Atomization Flow Field

2020 ◽  
Author(s):  
Tian Deng ◽  
Xingming Ren ◽  
Yaxuan Li
Keyword(s):  
Flow Field ◽  
High Speed ◽  
Large Scale ◽  
Gas Flow ◽  
Liquid Core ◽  
Average Diameter ◽  
Simulation Method ◽  
Spray Angle ◽  
Random Structure ◽  
Momentum Ratio

Abstract For the low-speed liquid injected into the high-speed strong turbulent gas flow in the same direction, the atomization is a transient-intensive spray, and there are many factors affecting and controlling the atomization. In this paper, the distribution and characteristics of the liquid breakup in the air atomized flow field are analyzed. A stochastic immersed model to simulate the liquid core is developed, in which, the liquid core is regarded as an immersed porous medium with a random structure, and the probability of existence is used to simulate the position of the liquid core. The initial fragmentation mechanism of the air blast atomization is applied as the global variables of the stochastic process. Using the above stochastic immersed model, combined with the Large Eddy Simulation method, the numerical simulation of the downstream flow field of a coaxial jet air atomizing nozzle is carried out. Additional force is added to the momentum equation in the LES model. Instantaneous air velocity at the air-liquid interface is characterized by instantaneous liquid phase velocity at the same time. The size of the initial atomized droplet satisfies a probability distribution, and once the large droplets are formed, the Lagrangian method is used to track the droplets. The comparison between the simulation results and the experimental results shows that this stochastic immersed model can quickly capture the information of length and position of the liquid nucleus. When the gas-liquid momentum ratio M is 3∼10000, the liquid core length can be predicted more accurately. When M>10, the prediction result is much better than phenomenological model. This model is capable of capturing flow field structures such as recirculation zones and large-scale vortices. The results of initial spray angle from experiment expression give slightly better agreement with this model. Increasing the momentum ratio leads to decreasing of the initial spray angle. The particle size of the droplets near the nozzle can be accurately predicted, especially when the gas velocity is large (bigger than 60 m/s), and the average diameter prediction error of the droplets is less than 10%.

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