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 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.

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%.

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 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.

Development, Analysis, and Validation of a Simultaneous Inlet Total Pressure and Swirl Distortion Generator

2020 ◽  
Author(s):  
Dustin J. Frohnapfel ◽  
K. Todd Lowe ◽  
Walter F. O’Brien
Keyword(s):  
Total Pressure ◽  
Experimental Validation ◽  
Computational Analysis ◽  
Pressure Recovery ◽  
Turbofan Engine ◽  
Full Field ◽  
Inlet Distortion ◽  
Swirl Angle ◽  
Total Pressure Recovery ◽  
Ground Test

Abstract Over the last decade, the Turbomachinery and Propulsion Research Laboratory at Virginia Tech has researched, invented, developed, computationally analyzed, experimentally tested, and improved turbofan engine inlet distortion generators. This effort began with modernizing and improving inlet total pressure distortion screens originally conceived over half a century ago; continued with the invention of inlet swirl distortion generators (StreamVanes™) made possible only through advances in modern additive manufacturing technology; and has, thus far, culminated in a novel combined device (ScreenVanes™) capable of simulating realistic flight conditions of coupled inlet total pressure and swirl distortion in a ground-test turbofan engine research platform. The present research focuses on the methodology development, computational analysis, and experimental validation of a novel simultaneous inlet total pressure and swirl distortion generator. A case study involving a single bend S-duct inlet distortion profile demonstrates the ability to generate a high-fidelity profile simulation, yet outlines a design process sufficiently generic for application to any arbitrary inlet geometry or distortion profile. A computational fluid dynamics simulation of the S-duct inlet provided the target profile extracted at the aerodynamic interface plane. Next, utilizing a method of inverse propagation, the planar distortion profile was propagated upstream to yield a flow field that could be manufactured by a distortion generator adequately isolated from turbomachinery effects. The total pressure distortion screen and swirl distortion StreamVane components were then designed and computationally analyzed. Upon successful computational reproduction of the S-duct inlet distortion profile, experimental hardware was fabricated and tested to validate the ScreenVane methodology and distortion generating device. Comparison of the S-duct manufactured distortion and the ScreenVane manufactured distortion was used as the primary criterion for profile replication success. Results from a computational analysis of both the S-duct and ScreenVane indicated excellent agreement in distortion pattern shape, extent, and intensity with full-field total pressure recovery and swirl angle profiles matching within approximately 0.80% and 2.6°, respectively. Furthermore, experimental validation of the ScreenVane indicated nearly identical full-field total pressure recovery and swirl angle profile replication of approximately 1.10% and 2.6°, respectively, when compared to the computational results. The investigation concluded that not only was the ScreenVane device capable of accurately simulating a complex inlet distortion profile, but also produced a viable device for full-scale turbofan engine ground test.

Flow field and performance analysis of an integrated diverterless supersonic inlet

2011 ◽  
Vol 115 (1170) ◽  
pp. 471-480 ◽  
Author(s):  
J. Masud
Keyword(s):  
Mass Flow ◽  
Total Pressure ◽  
Critical Mass ◽  
Wind Tunnel Test ◽  
Flow Behaviour ◽  
Pressure Recovery ◽  
Duct Flow ◽  
Supersonic Inlet ◽  
Total Pressure Recovery ◽  
And Performance

Abstract In this paper the computed flow and performance characteristics at low angle-of-attack (AOA) of an integrated diverterless supersonic inlet (DSI) are presented. The subsonic characteristics are evaluated at M∞ = 0·8 while the supersonic characteristics are evaluated at M∞= 1·7, which is near the design Mach number for the intake. In addition to the external flow features, the internal intake duct flow behaviour is also evaluated. The results of this study indicate effective boundary layer diversion due to the ‘bump’ compression surface in both subsonic and supersonic regimes. At M∞ = 1·7, the shockwave structure (oblique/normal shockwave) on the ‘bump’ compression surface and intake inlet is satisfactory at design (critical) mass flow rate. The intake duct flow behaviour at subsonic and supersonic conditions is generally consistent with ‘Y’ shaped intake duct of the present configuration. The secondary flow structure inside the duct has been effectively captured by present computations. The computed intake total pressure recovery at M∞ = 1·7 exhibits higher-than-conventional behaviour at low mass flow ratios, which is attributed to unique inlet design. Overall computed subsonic and supersonic total pressure recovery characteristics are satisfactory under the evaluated conditions and are also in agreement with wind tunnel test data.

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.

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