scholarly journals Удосконалення характеристик кільцевого вхідного пристрою авіаційної силової установки з гвинтовентилятором

2021 ◽  
pp. 11-18
Author(s):  
Олег Володимирович Жорник ◽  
Ігор Федорович Кравченко ◽  
Михайло Михайлович Мітрахович
Keyword(s):  
Total Pressure ◽  
Influential Factor ◽  
Recovery Factor ◽  
Pressure Recovery ◽  
Input Device ◽  
Navier Stokes Equation ◽  
Element Analysis ◽  
Turboprop Engine ◽  
Pressure Recovery Factor ◽  
Full Pressure

The article considers the method of improving the characteristics of the ring inlet device, taking into account the influence of the propeller of an aircraft power plant with a turboprop engine. It is shown that increasing the total pressure loss in the inlet device by 5% increases, approximately, the specific fuel consumption by 3% and reduces engine thrust by 6%, and uneven flow at the inlet to the engine is the cause of unstable compressor of the turboprop engine. It is proposed to improve the characteristics of the input device by modifying the shape of its shell and channel. Evaluation of the influence of the shape of the shell and the channel of the annular axial VP on its main aerodynamic characteristics, taking into account the non-uniformity of the flow on the fan in the calculated mode of operation of the SU is carried out by calculating the full pressure recovery factor. The object of the study is an annular axial input device in front of which is a coaxial fan turboprop fan. The process of modeling the influence of the shape of the shell and the channel on the recovery factor of total pressure, circular and radial non-uniformity of the flow through the input device is implemented in the software system of finite element analysis ANSYS CFX. Geometric models of coaxial screw fan, fairing and inlet device are built in ANSYS SpaceClaim and transferred using the built-in import function in ANSYS Workbench. Block-structured grid models of air propellers of the first and second rows of the fan in the amount of 1.9 million, fairing and inlet device, in the amount of 3.9 million, are built in the ANSYS TurboGrid environment. The standard Stern (Shear Stress Transport) Gamma Theta Transition was used to close the Navier-Stokes equation system. Based on the results of mathematical modeling of flow in coaxial fans and subsonic ring inlet device on the maximum cruising mode of the turboprop engine, the full pressure recovery factor is calculated and it is established that the most influential factor that increases its full pressure recovery factor.

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.

DEGREE OF REGENERATION OPTIMIZATION FOR CYCLES OF MICROGAS TURBINE PLANTS

2020 ◽  
Vol 3 ◽  
pp. 59-66
Author(s):  
A.V. DOLOGLONYAN ◽  
V.T. MATVIINKO
Keyword(s):  
Mathematical Model ◽  
Heat Exchanger ◽  
Surface Area ◽  
Hydraulic Resistance ◽  
Recovery Factor ◽  
Pressure Recovery ◽  
Area Optimization ◽  
Pressure Recovery Factor ◽  
The Mathematical Model ◽  
Regenerative Cycle

A consideration subject in article is the mathematical model of pressure recovery factor of microgas turbine plants (MGTP) regenerators which considers dependence of hydraulic resistance of the heat–exchanger on the its surface area. Optimization of a regenerative cycle of MGTP and a cycle with regeneration and the turbocompressor utilizer for the purpose of further increase in their profitability is performed. It is established that use of the offered model of pressure recovery factor on the air and gas side allows to find degree of regeneration heattechnical optimum. This model can be used at simplified and predesign of MGTP.

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.

Improving the Efficiency of a Hydro-Turbine System by Vortex Generators

2011 ◽  
Vol 354-355 ◽  
pp. 636-641 ◽  
Author(s):  
Hua Chen Pan ◽  
Shu Li Hong
Keyword(s):  
Working Conditions ◽  
Draft Tube ◽  
Vortex Generators ◽  
Recovery Factor ◽  
Pressure Recovery ◽  
Hydro Turbine ◽  
Turbine Performance ◽  
Pressure Recovery Factor ◽  
Inside Wall

This paper studies the effect of vortex generators on hydro-turbine working performances. The study was carried out on a hydro-turbine system provided by Waterpumps Oy, Finland. First, the performance of the hydro-turbine system was analyzed with a CFD solver under different working conditions. Then, the hydro-turbine performance was examined with several vortex generators installed uniformly on the inside wall of the draft tube near its inlet. The turbine system’s efficiencies were compared for cases with and without vortex generators. Results show that turbine performs better when there are vortex generators installed in the draft tube of which the pressure recovery factor is much higher.

A Jet Pump Design Theory

1960 ◽  
Vol 82 (4) ◽  
pp. 947-960 ◽  
Author(s):  
T. W. Van Der Lingen
Keyword(s):  
Design Theory ◽  
Momentum Equation ◽  
Operating Conditions ◽  
Recovery Factor ◽  
Pressure Recovery ◽  
Jet Pump ◽  
Pump Design ◽  
Jet Pumps ◽  
Pressure Recovery Factor ◽  
General Method

A compressible flow jet pump theory is evolved which can be more easily interpreted for design purposes than existing theories. It consists of a one-dimensional analysis based on the momentum equation and on complete mixing, used in conjunction with an over-all pressure recovery factor which is found experimentally. Tests on a small jet pump are described and from the results it is shown that the overall pressure recovery factor can be related to a single parameter in the analysis for all operating conditions of each general pump configuration. In this way a general method for the correlation of results and for the design of jet pumps is established.

Assessing the Impact of the Inlet Total Pressure Distortion on the Turbofan Thrust

2018 ◽  
pp. 19-30
Author(s):  
Yu. A. Ezrokhi ◽  
E. A. Khoreva
Keyword(s):  
Total Pressure ◽  
External Compression ◽  
Average Value ◽  
Inlet Distortion ◽  
Air Inlet ◽  
Engine Thrust ◽  
Relative Value ◽  
Main Effect ◽  
Pressure Recovery Factor ◽  
The Impact

The paper considers techniques to develop a mathematical model using a method of «parallel compressors». The model is intended to estimate the impact of the air inlet distortion on the primary parameters of the aero-engine.  The paper presents rated estimation results in the context of twin spool turbofan design for two typical cruiser modes of flight of the supersonic passenger jet. In estimation the base values σbase and the average values of the inlet ram recovery σave remained invariable. Thus, parametrical calculations were performed for each chosen relative value of the area of low-pressure region.The paper shows that an impact degree of the inlet distortion on the engine thrust for two modes under consideration is essentially different. In other words, if in the subsonic mode the impact assessment can be confined only to taking into account the influence of decreasing average values of the inlet total pressure, the use of such an assumption in the supersonic cruiser mode may result in considerable errors.With invariable values of the pressure recovery factor at the engine intake, which correspond to the speed of flight for a typical air inlet of external compression σbase, and average value σave, a parameter Δσuneven  has the main effect on the engine thrust, and degree of this effect essentially depends on a difference between σave and σbase values.

Effect of the turning angle on the flow and performance characteristics of long S-shaped circular diffusers

2003 ◽  
Vol 217 (1) ◽  
pp. 29-41 ◽  
Author(s):  
R B Anand ◽  
L Rai ◽  
S N Singh
Keyword(s):  
Total Pressure ◽  
Static Pressure ◽  
Area Ratio ◽  
Secondary Flows ◽  
Performance Characteristics ◽  
Pressure Recovery ◽  
Recovery Coefficient ◽  
Turning Angle ◽  
And Performance ◽  
Pressure Recovery Coefficient

The effect of the turning angle on the flow and performance characteristics of long S-shaped circular diffusers (length-inlet diameter ratio, L/Di = 11:4) having an area ratio of 1.9 and centre-line length of 600 mm has been established. The experiments are carried out for three S-shaped circular diffusers having angles of turn of 15°/15°, 22.5°/22.5° and 30°/30°. Velocity, static pressure and total pressure distributions at different planes along the length of the diffusers are measured using a five-hole impact probe. The turbulence intensity distribution at the same planes is also measured using a normal hot-wire probe. The static pressure recovery coefficients for 15°/15°, 22.5°/22.5° and 30°/30° diffusers are evaluated as 0.45, 0.40 and 0.35 respectively, whereas the ideal static pressure recovery coefficient is 0.72. The low performance is attributed to the generation of secondary flows due to geometrical curvature and additional losses as a result of the high surface roughness (~0.5 mm) of the diffusers. The pressure recovery coefficient of these circular test diffusers is comparatively lower than that of an S-shaped rectangular diffuser of nearly the same area ratio, even with a larger turning angle (90°/90°), i.e. 0.53. The total pressure loss coefficient for all the diffusers is nearly the same and seems to be independent of the angle of turn. The flow distribution is more uniform at the exit for the higher angle of turn diffusers.

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