scholarly journals Обґрунтування моделі турбулентної в’язкості для дослідження характеристик співвісного гвинтовентилятора і вхідного пристрою ГТД

2021 ◽  
pp. 35-39
Author(s):  
Олег Володимирович Жорник ◽  
Ігор Федорович Кравченко ◽  
Михайло Михайлович Мітрахович ◽  
Олеся Валеріїна Денисюк
Keyword(s):  
Mathematical Modeling ◽  
Total Pressure ◽  
Turbulent Viscosity ◽  
Flight Test ◽  
Recovery Factor ◽  
Pressure Recovery ◽  
Recovery Coefficient ◽  
Transition Analysis ◽  
Total Pressure Recovery ◽  
Pressure Recovery Factor

The issues of substantiation of the most rational, based on adequacy, model of turbulent viscosity for mathematical modeling of the flow near the propfan and in the inlet of the turbine-propeller engine are considered. It was found that at present there is no universal turbulence model for determining the parameters of the boundary layer, energy loss in the flow, and laminar-turbulent transition. Analysis of the results of previous studies showed that there is a need to select and justify a turbulent viscosity model for each type of research object. The task of modeling the flow near the propfan and in the inlet device of the power plant was performed using the ANSYS CFX software product, which allows using various standard mathematical models and tools for modeling turbulent flow. The object of research is an annular axial inlet device, in front of which there is a coaxial propfan with two rows of propellers: the first row has eight blades, the second - six. 7 types of models of turbulent viscosity, which most fully describe the phenomena in the flow around the propfan and the inlet device, have been investigated: k-ωmodel; SSТ (shear stress transport) SST Transitional №1 Fully turbulence; SST Transitional №2 Specified Intermittency; SST Transitional №3 Gamma model; SST Transitional №4 Gamma theta model; SST Transitional №5 Intermittency. The results of mathematical modeling of the flow near the propfan and in the inlet device at the corresponding operating mode of the turbopropfan engine using the selected models of turbulent viscosity, the total pressure value in front of and behind the inlet device was obtained to determine the total pressure recovery coefficient in it and the value of the propfan thrust. The value of the recovery factor of the total pressure in the inlet device and the propfan thrust are compared with the flight test data of the prototype. An analysis of the comparison of the values of the total pressure recovery factor in the inlet device and the propfan thrust showed that the use of the SST Transitional №4 Gamma theta model allows obtaining the value of the total pressure recovery factor in the inlet device and the propfan thrust that is closest to the flight test results.

Growth of the total pressure recovery factor in a flow behind a shock wave emerging from a channel with concave corners in cross section

2003 ◽  
Vol 29 (5) ◽  
pp. 385-387 ◽  
Author(s):  
T. V. Bazhenova ◽  
V. V. Golub ◽  
A. L. Kotel’nikov ◽  
A. S. Chizhikov ◽  
M. V. Bragin
Keyword(s):  
Shock Wave ◽  
Cross Section ◽  
Total Pressure ◽  
Recovery Factor ◽  
Pressure Recovery ◽  
Total Pressure Recovery ◽  
Pressure Recovery Factor

scholarly journals Influence of Propeller Slipstream on the Flow Field of S-Shaped Intake

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Shuili Ren ◽  
Peiqing Liu
Keyword(s):  
Flow Field ◽  
Total Pressure ◽  
Engine Performance ◽  
Pressure Recovery ◽  
Navier Stokes ◽  
Navier Stokes Equation ◽  
Recovery Coefficient ◽  
Distortion Coefficient ◽  
Total Pressure Recovery ◽  
Pressure Recovery Coefficient

For turboprop engine, the S-shaped intake affects the engine performance and the propeller is not far in front of the inlet of the S-shaped intake, so the slipstream inevitably affects the flow field in the S-shaped intake and the engine performance. Here, an S-shaped intake with/without propeller is studied by solving Reynolds-averaged Navier-Stokes equation employed SST k-ω turbulence model. The results are presented as time-averaged results and transient results. By comparing the flow field in S-shaped intake with/without propeller, the transient results show that total pressure recovery coefficient and distortion coefficient on the AIP section vary periodically with time. The time-averaged results show that the influence of propeller slipstream on the performance of S-shaped intake is mainly circumferential interference and streamwise interference. Circumferential interference mainly affects the secondary flow in the S-shaped intake and then affects the airflow uniformity; the streamwise interference mainly affects the streamwise flow separation in the S-shaped intake and then affects the total pressure recovery. The total pressure recovery coefficient on the AIP section for the S-shaped intake with propeller is 1%-2.5% higher than that for S-shaped intake without propeller, and the total pressure distortion coefficient on the AIP section for the S-shaped intake with propeller is 1%-12% higher than that for the S-shaped intake without propeller. However, compared with the free stream flow velocity ( Ma = 0.527 ), the influence of the propeller slipstream belongs to the category of small disturbance, which is acceptable for engineering applications.

Numerical Study on the Plasma Generated by Different Discharge Modes at the Upstream of Fuel Jet in Scramjet Combustor

2013 ◽  
Vol 444-445 ◽  
pp. 1345-1349
Author(s):  
Si Yin Zhou ◽  
Wan Sheng Nie ◽  
Bo He ◽  
Xue Ke Che ◽  
Xue Min Tian
Keyword(s):  
Total Pressure ◽  
Recirculation Zone ◽  
Pressure Recovery ◽  
Flow Conditions ◽  
Recovery Coefficient ◽  
Discharge Mode ◽  
Scramjet Combustor ◽  
Fuel Jet ◽  
Total Pressure Recovery ◽  
Pressure Recovery Coefficient

How to enhance the combustion and reduce the total pressure loss in scramjet combustor are very critical for the practical application of hypersonic aircraft. Based on the dominant thermal mechanism of arc plasma, the plasma generated in combustor is regarded as a promising method to improve the combustion. As a result, the combustor model with transverse fuel jet and plasma generated by two discharge modes at the upstream of flameholding cavity is established and it is used to study the mechanism of fuel mixing enhancement through numerical investigation. The results show that an oblique shock wave would be formed at the upstream of the pseudo small plasma hump, and interact with the separation shock wave induced by the transverse jet. This results in the recirculation zone at the upstream of fuel jet being enlarged obviously. Besides that, under the non-reaction flow conditions, the total pressure recovery coefficient increases due to the plasma generated. However, the total pressure recovery coefficient varies apparently and the shear layer above the cavity is fluctuant when the plasma is generated by periodical discharge mode. While under the reaction flow conditions, the shear layer develops thicker and the total pressure recovery coefficient decreases. And due to the existing of plasma, the mole fraction of product water increases. But compared with the steady discharge mode, the level of water is lower and the total pressure recovery coefficient decreases more under the periodical discharge mode. Though the plasma generated by steady discharge mode shows better performance in assisting combustion and reducing the pressure loss, considering the energy saving and the use of different parameters of the periodical discharge, the same effects of enhancing the fuel mixing through enlarging the recirculation zone located at the upstream of fuel jet and promoting the mass exchange of cavity can be reached. More numerical experiments have to be done to optimize the parameters of periodical discharge plasma to receive a best improvement on the performance of scramjet combustor.

Influence of Area Distribution With Fixed Trajectory on Serpentine Intake Duct Performance

2012 ◽  
Author(s):  
Ritesh Gaur ◽  
Vimala Narayanan ◽  
S. Kishore Kumar
Keyword(s):  
Total Pressure ◽  
Pressure Recovery ◽  
Maximum Pressure ◽  
Recovery Coefficient ◽  
Cross Sectional ◽  
Fixed Boundary ◽  
Area Distribution ◽  
Pressure Recovery Factor ◽  
Minimum Distortion ◽  
Pressure Recovery Coefficient

Performance of intake duct with fixed inlet trajectory and different area distributions have been analyzed using a commercial CFD (Computational Fluid Dynamics) software. The performance have been evaluated for fixed boundary conditions. The area distributions studied are defined by varying cross sectional area at different locations of intake duct by keeping the inlet and exit area same. The performance of the intake ducts are studied in terms of the pressure recovery coefficient, total pressure loss, pressure recovery factor and distortion coefficient in the present work. The motion caused by the change in centerline curvature is analyzed. The objective of the work is to derive a shape of the duct with minimum distortion of the flow and maximum pressure recovery.

Numerical analysis on the conceptual design of an air-breathing engine inlet working in mach number 3∼5.5

2021 ◽  
pp. 095441002110113
Author(s):  
Chao Huo ◽  
Zhenhua Yang ◽  
Zhengze Zhang ◽  
Peijin Liu
Keyword(s):  
Mach Number ◽  
Total Pressure ◽  
Back Pressure ◽  
Pressure Recovery ◽  
Shock Train ◽  
Recovery Coefficient ◽  
Air Breathing ◽  
Supersonic Inlet ◽  
Total Pressure Recovery ◽  
Pressure Recovery Coefficient

Based on the equal-intensity shock theory, this article designed a supersonic inlet working in Mach number 3.0∼5.5 with the background of an air-breathing engine. The inlet applied the four-shock train mixed compression configuration and inserted a sidewall compression at the beginning of the isolator. Through developing effective 3D RANS computations validated by current experiments, the performance of the designed inlet was identified. The designed inlet self-starts at freestream Mach number Ma∞ = 3.0 under which the total pressure recovery coefficient has dramatic increment, and the aerodynamic choking at the inlet throat no longer presents; the inlet keeps working at all studied flight states with zero angle of attack (AoA) and achieves shock-on-lip at the design point Ma∞ = 5.0. Both positive and negative AoAs can disrupt the equal-intensity shock allocations, which degrade the inlet performance. The inlet obtains maximum total pressure recovery coefficient at zero AoA. The maximum back pressure at Ma∞ = 3.0∼5.5 obtained by the inlet surpasses the requirements and keeps a certain margin. The inlet performance basically meets all the goals proposed by the engine.

Aerodynamic Design Investigation on Inlet-Exhaust System Using Super-Ellipse Method

2012 ◽  
Vol 246-247 ◽  
pp. 446-450
Author(s):  
Yue Feng Li ◽  
Qing Zhen Yang ◽  
Xue Jiao Deng
Keyword(s):  
Cross Section ◽  
Total Pressure ◽  
Exhaust System ◽  
Shape Index ◽  
Pressure Recovery ◽  
Recovery Coefficient ◽  
Thrust Coefficient ◽  
Ellipse Method ◽  
Total Pressure Recovery ◽  
Pressure Recovery Coefficient

Generally, the shape index n is selected in a form when design the inlet-exhaust system using traditional super-ellipse method. Unfortunately, this selection process is time-consuming and not precise enough, so the cross-section designed by super-ellipse method may get distortions easily, which influences the inner flow and the total pressure of the inlet-exhaust system greatly. Associating the shape index n with the variation pattern of the inlet-exhaust cross-section, an improved super-ellipse method is developed to design the inlet-exhaust system. This method ensures the precision and uniqueness of shape index n for any cross-section in an adaptive way. The numerical simulation results show that the S-shape inlet designed using this method has high total pressure recovery coefficient and lower distortion coefficient, the S-shaped nozzle has high total pressure recovery coefficient and thrust coefficient.

Design of S-Shaped Submerged Inlet

2011 ◽  
Vol 291-294 ◽  
pp. 349-354
Author(s):  
Guang Lin He ◽  
Xiao Lin Li
Keyword(s):  
Cross Section ◽  
Total Pressure ◽  
Aerodynamic Performance ◽  
New Method ◽  
Pressure Recovery ◽  
Recovery Coefficient ◽  
Distortion Coefficient ◽  
Total Pressure Recovery ◽  
The Cross ◽  
Pressure Recovery Coefficient

The influence of centerline and the cross-section variation to aerodynamic performance of the inlet was researched in a wider range. A new method of measuring the total pressure recovery coefficient and total pressure distortion coefficient of the inlet was proposed. Based on the loitering aircraft, a s-shaped inlet was designed to meet the needs of stable flight of loitering aircraft, whose total pressure recovery coefficient is 93.2% and total pressure distortion coefficient is 1.2%.

Parameterization and optimization design of a two-dimensional axisymmetric hypersonic inlet

2021 ◽  
pp. 095441002110295
Author(s):  
Shangcheng Xu ◽  
Yi Wang ◽  
Zhenguo Wang ◽  
Xiaoqiang Fan ◽  
Bing Xiong
Keyword(s):  
Total Pressure ◽  
Optimization Design ◽  
Separation Bubble ◽  
Pressure Recovery ◽  
Two Dimensional ◽  
Recovery Coefficient ◽  
Hypersonic Inlet ◽  
Contraction Ratio ◽  
Total Pressure Recovery ◽  
Pressure Recovery Coefficient

Optimization method, as a promising way to improve inlet aerodynamic performance, has received increasing attention. The present research is undertaken to design a two-dimensional axisymmetric hypersonic inlet using parametric optimization. The inlet configuration is parameterized and optimized in consideration of total pressure recovery and starting performance. A Pareto front is obtained by solving the multi-objective optimization problem. Then, the flow structures of the optimized inlets are analyzed and the starting performances are evaluated. Results show that the total pressure loss mainly occurs in the internal contraction section, especially near the inlet entrance, and therefore the total pressure recovery coefficient can be greatly improved by decreasing external compression. As a result, the guidance for designing high-performance inlets is concluded. Besides, it is found that as the internal contraction ratio increases, the inlet starting ability becomes worse, which attributes to the larger separation bubble at the inlet entrance. Finally, the total pressure recovery coefficient and the starting Mach number of the optimized inlets are obtained, which can be a reference for engineering design.

Flow Development Through An S-Shaped Diffusing Duct

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Jinfang Teng ◽  
Junda Feng ◽  
Dongrun Wu ◽  
Pan He ◽  
Mingmin Zhu
Keyword(s):  
Total Pressure ◽  
Internal Flow ◽  
Adverse Pressure Gradient ◽  
Reynolds Stress Model ◽  
Pressure Recovery ◽  
Experimental Result ◽  
Recovery Coefficient ◽  
Flow Development ◽  
Total Pressure Recovery ◽  
Pressure Recovery Coefficient

AbstractThis paper focuses on the internal flow development of an S-shaped diffusing duct. Based on the experimental result of total pressure recovery coefficient, the Reynolds stress model (RSM) was selected as a suitable turbulence model for the present study. The numerical results show that 6.2 times the area ratio of the exit to inlet and the aggressive deflection at the first bend of the lower wall lead to strong adverse pressure gradient and very large flow separation, and create a pair of counter-rotating vortices along streamwise direction. The duct diffuser efficiency is 72.37 %. The area-averaged total pressure recovery coefficient at the exit of the duct is 0.9814, and the synthesis distortion index DC (60) is 0.7081.

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