Investigation on Shock Oscillation Phenomenon in a Supersonic Air Inlet

2011 ◽  
Author(s):  
Tomohiro Nakayama ◽  
Tetsuya Sato ◽  
Masahiro Akatsuka ◽  
Atsushi Hashimoto ◽  
Takayuki Kojima ◽  
...  
Keyword(s):  
Air Inlet ◽  
Oscillation Phenomenon ◽  
Shock Oscillation

Study of Starting Problem of Axisymmetric Divergent Dual Throat Nozzle

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Yangsheng Wang ◽  
Jinglei Xu ◽  
Shuai Huang
Keyword(s):  
Cavity Length ◽  
Expansion Ratio ◽  
Divergence Angle ◽  
Nozzle Throat ◽  
Convergence Angle ◽  
Cavity Bottom ◽  
Oscillation Phenomenon ◽  
Thrust Vector ◽  
Shock Oscillation ◽  
Simulation Results

Compared to the conventional axisymmetric dual throat nozzle, the axisymmetric divergent dual throat nozzle (ADDTN) can offer larger thrust vector angles. However, the starting problem maybe exists in the ADDTN and results in a huge thrust loss. In this paper, the ADDTN starting problem has been studied by steady and unsteady numerical simulations. The effects of nozzle geometric parameters on internal nozzle performance have been discussed in detail, including cavity divergence angle, cavity convergence angle, cavity length, expansion ratio, rounding radius at the nozzle throat, and rounding radius at the cavity bottom. And, the shock oscillation phenomenon is found inside the recessed cavity in some high-expansion ratio configurations. In addition, a bypass is proposed in this study to solve the ADDTN starting problem. The main numerical simulation results show that the expansion ratio is the most sensitive parameter affecting the starting characteristic of ADDTN, followed by the cavity divergence angle and the cavity length. And, among these parameters, the parameters of cavity convergence angle and rounding radius at the cavity bottom contribute the least to the starting problem. Besides, the ADDTN configurations of large rounding radius at the nozzle throat tend to start.

Numerical Simulation of Terminal Shock Oscillation in Over/Under Turbine-Based Combined-Cycle Inlet

2017 ◽  
Vol 0 (0) ◽  
Author(s):  
Jun Liu ◽  
Huacheng Yuan ◽  
Meng Yao ◽  
Ning Ge
Keyword(s):  
Numerical Simulation ◽  
Separation Bubble ◽  
Control Point ◽  
Simulation Method ◽  
Combined Cycle ◽  
Key Factors ◽  
Oscillation Phenomenon ◽  
Shock Oscillation ◽  
Main Factors ◽  
Unsteady Numerical Simulation

AbstractThe physical characteristics of self-sustain shock oscillation and the key factors that affect the shock oscillation in turbine-based combined-cycle(TBCC) inlet were investigated through unsteady numerical simulation method in this paper. The terminal shock oscillation in the throat was caused by the separation bubble appeared in the lower wall of the turbojet flowpath. The angle of the splitter and the offset of the diffuser were the main factors which affect the characteristics of the shock oscillation. When the angle of the splitter increased from 0 deg to 12 deg, the frequency of terminal shock increased from 100Hz to 133Hz; while when it was greater than 18 deg the terminal shock oscillation phenomenon disappeared. Different offset of the turbojet diffuser affect the motion of terminal shock in the inlet. When the y-coordinate value of the control point (y

A TIP OSCILLATION PHENOMENON

1987 ◽  
Vol 48 (C6) ◽  
pp. C6-215-C6-218
Author(s):  
M. Drechsler ◽  
A. Maas
Keyword(s):  
Oscillation Phenomenon

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.

A critique of the F-14A air inlet control system - From development to production status

1974 ◽  
Author(s):  
H. HUTTENLOCHER ◽  
R. STEELE ◽  
C. THOMSON ◽  
B. MELLINGER
Keyword(s):  
Control System ◽  
Air Inlet

scholarly journals Microencapsulation ofβ-Carotene by Spray Drying: Effect of Wall Material Concentration and Drying Inlet Temperature

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Luiz C. Corrêa-Filho ◽  
Maria M. Lourenço ◽  
Margarida Moldão-Martins ◽  
Vítor D. Alves
Keyword(s):  
Antioxidant Activity ◽  
Spray Drying ◽  
Encapsulation Efficiency ◽  
Fruits And Vegetables ◽  
Wall Material ◽  
Inlet Temperature ◽  
Carotene Content ◽  
Arabic Gum ◽  
Air Inlet ◽  
Adverse Environmental Conditions

Carotenoids are a class of natural pigments found mainly in fruits and vegetables. Among them,β-carotene is regarded the most potent precursor of vitamin A. However, it is susceptible to oxidation upon exposure to oxygen, light, and heat, which can result in loss of colour, antioxidant activity, and vitamin activity. Thus, the objective of this work was to study the microencapsulation process ofβ-carotene by spray drying, using arabic gum as wall material, to protect it against adverse environmental conditions. This was carried out using the response surface methodology coupled to a central composite rotatable design, evaluating simultaneously the effect of drying air inlet temperature (110-200°C) and the wall material concentration (5-35%) on the drying yield, encapsulation efficiency, loading capacity, and antioxidant activity. In addition, morphology and particles size distribution were evaluated. Scanning electron microscopy images have shown that the particles were microcapsules with a smooth surface when produced at the higher drying temperatures tested, most of them having a diameter lower than 10μm. The conditions that enabled obtaining simultaneously arabic gum microparticles with higherβ-carotene content, higher encapsulation efficiency, and higher drying yield were a wall material concentration of 11.9% and a drying inlet temperature of 173°C. The systematic approach used for the study ofβ-carotene microencapsulation process by spray drying using arabic gum may be easily applied for other core and wall materials.

scholarly journals Experimental analysis and ANN prediction on performances of finned oval-tube heat exchanger under different air inlet angles with limited experimental data

Open Physics ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 968-980
Author(s):  
Xueping Du ◽  
Zhijie Chen ◽  
Qi Meng ◽  
Yang Song
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Heat Exchanger ◽  
Correlation Equation ◽  
Tube Heat Exchanger ◽  
Flow Friction ◽  
Air Inlet ◽  
Comparison Results ◽  
Wide Range ◽  
Oval Tube

Abstract A high accuracy of experimental correlations on the heat transfer and flow friction is always expected to calculate the unknown cases according to the limited experimental data from a heat exchanger experiment. However, certain errors will occur during the data processing by the traditional methods to obtain the experimental correlations for the heat transfer and friction. A dimensionless experimental correlation equation including angles is proposed to make the correlation have a wide range of applicability. Then, the artificial neural networks (ANNs) are used to predict the heat transfer and flow friction performances of a finned oval-tube heat exchanger under four different air inlet angles with limited experimental data. The comparison results of ANN prediction with experimental correlations show that the errors from the ANN prediction are smaller than those from the classical correlations. The data of the four air inlet angles fitted separately have higher precisions than those fitted together. It is demonstrated that the ANN approach is more useful than experimental correlations to predict the heat transfer and flow resistance characteristics for unknown cases of heat exchangers. The results can provide theoretical support for the application of the ANN used in the finned oval-tube heat exchanger performance prediction.

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