Numerical Simulation on Hypersonic Combustion of Hydrogen-Fueled Scramjet Combustor with Parallel Strut Fuel Injection at a Flight Mach Number of 7

2015 ◽  
Vol 766-767 ◽  
pp. 1044-1049

Removed due to plagiarism. The original was published as: Numerical Investigation of Inlet-Combustor Interactions for a Scramjet Hydrogen-Fueled Engine at a Flight Mach number of 8. Authors: Edder Rabadan and Bernhard Weigand 18th AIAA/3AF International Space Planes and Hypersonic Systems and Technologies Conference, Tours, France, 2012. Paper ID AIAA-2012-5926, DOI: 10.2514/6.2012-5926

Author(s):  
A. Chernobrovkin ◽  
B. Lakshminarayana

A viscous flow solver based on the Runge-Kutta scheme has been modified for the numerical investigation of the aerothermal field due to the leading edge film cooling at a compound angle. An existing code has been modified to incorporate multi-block capabilities. Good agreement with the measured data has been achieved. Results of the numerical investigation have been used to analyze the vortex structure associated with the coolant jet-freestream interaction to understand the contribution of different vortices on the cooling effectiveness and aerothermal losses. Two counter-rotating vortices generated by the interaction between the mainflow and the coolant jet have been found to have a major influence in decreasing the cooling efficiency through strong entrainment of the hot fluid. Numerical simulation was carried out to investigate the influence of the inlet Mach number, inlet turbulence intensity, and length scale on the aerothermal field due to the leading edge film cooling. Variation of the inlet Mach number leads to a minor modification of the cooling effectiveness, and this is predominantly caused by the modified pressure gradient. Increased turbulence intensity has profound effect on the cooling near the leading edge. Adiabatic effectiveness downstream of the second row of coolant holes is less sensitive to a change in turbulence intensity. Results of the numerical simulation indicate that the turbulence length scale has a significant effect on the accuracy of the numerical prediction of film cooling. Not only the inlet turbulence intensity but also the turbulence length scale should be accurately set to achieve a reliable numerical prediction of the heat and mass transfer due to film cooling.


Author(s):  
Huishe Wang ◽  
Qingjun Zhao ◽  
Xiaolu Zhao ◽  
Jianzhong Xu

A detailed unsteady numerical simulation has been carried out to investigate the shock systems in the high pressure (HP) turbine rotor and unsteady shock-wake interaction between coupled blade rows in a 1+1/2 counter-rotating turbine (VCRT). For the VCRT HP rotor, due to the convergent-divergent nozzle design, along almost all the span, fishtail shock systems appear after the trailing edge, where the pitch averaged relative Mach number is exceeding the value of 1.4 and up to 1.5 approximately (except the both endwalls). A group of pressure waves create from the suction surface after about 60% axial chord in the VCRT HP rotor, and those waves interact with the inner-extending shock (IES). IES first impinges on the next HP rotor suction surface and its echo wave is strong enough and cannot be neglected, then the echo wave interacts with the HP rotor wake. Strongly influenced by the HP rotor wake and LP rotor, the HP rotor outer-extending shock (OES) varies periodically when moving from one LP rotor leading edge to the next. In VCRT, the relative Mach numbers in front of IES and OES are not equal, and in front of IES, the maximum relative Mach number is more than 2.0, but in front of OES, the maximum relative Mach number is less than 1.9. Moreover, behind IES and OES, the flow is supersonic. Though the shocks are intensified in VCRT, the loss resulted in by the shocks is acceptable, and the HP rotor using convergent-divergent nozzle design can obtain major benefits.


2011 ◽  
Vol 19 (03) ◽  
pp. 177-183 ◽  
Author(s):  
JIN-BO CHEN ◽  
QING-GANG QIU

The technique of horizontal-tube falling film has been used in the cooling and heating industries such as refrigeration systems, heating systems and ocean thermal energy conversion systems. The comprehensive performance of evaporator is directly affected by the film distribution characteristics outside tubes. In this paper, numerical investigation was performed to predict the film characteristics outside the tubes in horizontal-tube falling film evaporator. The effects of liquid flow rate, tube diameter and the circular degree of tube on the film thickness were presented. The numerical simulation results were compared with that of the empirical equations for calculating the falling film thickness, and agreements between them were reasonable. Numerical simulation results show that, at the fixed fluid flow density, the liquid film is thicker on the upper and lower tube and the thinnest liquid film appears at angle of about 120°. The results also indicate that, when the fluid flow density decreases to a certain value, the local dryout spot on the surface of the tube would occur. In addition, the film thickness decreases with the increases of the tube diameter at the fixed fluid flow density.


2000 ◽  
Author(s):  
Fahua Gu ◽  
Abraham Engeda ◽  
Mike Cave ◽  
Jean-Luc Di Liberti

Abstract A numerical simulation is performed on a single stage centrifugal compressor using the commercially available CFD software, CFX-TASCflow. The steady flow is obtained by circumferentially averaging the exit fluxes of the impeller. Three runs are made at design condition and off-design conditions. The predicted performance is in agreement with experimental data. The flow details inside the stationary components are investigated, resulting in a flow model describing the volute/diffuser interaction at design and off-design conditions. The recirculation and twin vortex structure are found to explain the volute loss increase at lower and higher mass flows, respectively.


2018 ◽  
Vol 857 ◽  
pp. 878-906 ◽  
Author(s):  
T. Nagata ◽  
T. Nonomura ◽  
S. Takahashi ◽  
Y. Mizuno ◽  
K. Fukuda

In this study, direct numerical simulation of the flow around a rotating sphere at high Mach and low Reynolds numbers is conducted to investigate the effects of rotation rate and Mach number upon aerodynamic force coefficients and wake structures. The simulation is carried out by solving the three-dimensional compressible Navier–Stokes equations. A free-stream Reynolds number (based on the free-stream velocity, density and viscosity coefficient and the diameter of the sphere) is set to be between 100 and 300, the free-stream Mach number is set to be between 0.2 and 2.0, and the dimensionless rotation rate defined by the ratio of the free-stream and surface velocities above the equator is set between 0.0 and 1.0. Thus, we have clarified the following points: (1) as free-stream Mach number increased, the increment of the lift coefficient due to rotation was reduced; (2) under subsonic conditions, the drag coefficient increased with increase of the rotation rate, whereas under supersonic conditions, the increment of the drag coefficient was reduced with increasing Mach number; and (3) the mode of the wake structure becomes low-Reynolds-number-like as the Mach number is increased.


2012 ◽  
Vol 571 ◽  
pp. 701-705
Author(s):  
Hui Yang ◽  
Feng Li ◽  
Bai Gang Sun ◽  
Dan Dan Tian ◽  
Yao Ying Song ◽  
...  

Structures of liquid-fuel injection in supersonic crossflow is studied experimentally. Schemes of flush-wall injector and aviation kerosene are selected. The conditions of the supersonic freestream are kept constant (total pressure is 0.5MPa, total temperature is 500K and Mach number is 2) and the diameter of the injector is fixed as 0.5mm, while seven scenarios of injection angle and three scenarios of injection driven pressure are discussed. Both methods of schlieren and planar laser induced fluorescence (PLIF) techniques are implemented to obtain the visual images of the liquid-fuel injection. The penetration height of fuel is analyzed quantitatively with the aid of Photoshop and Origin. The results serve not only the future computational simulation but also combined scheme of flush-wall injector and other combustor configurations.


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