183 Multi-point measurement of temperature fields in a turbulent boundary layer developing under non-uniformly heated wall boundary conditions

An experimental study of the wall temperature fluctuations under different thermal-wall boundary conditions was carried out. Statistics obtained from the experiments are compared with existing experimental and numerical data. The wall temperature fields are also examined in terms of the coherent thermal structures. In addition the effect of the thermal entrance region on the wall temperature distribution is also studied. For water flow in a flume and in a rectangular channel, the mean spacing of the thermal streaks does not depend on the thermal entrance length and on the type of thermal-wall boundary conditions. The wall temperature fluctuations depend strongly on the type of wall thermal boundary conditions. Overall, the picture that emerges from this investigation confirms the hypothesis that moderate-Prandtl-number heat transfer at a solid wall is governed by the large-scale coherent flow structures.

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Research on Flow and Temperature Fields in Aircraft Engines

The Open Mechanical Engineering Journal ◽

10.2174/1874155x01408010731 ◽

2014 ◽

Vol 8 (1) ◽

pp. 731-738 ◽

Cited By ~ 1

Author(s):

Guochang Zhao ◽

Daniel X. Zhao ◽

Jing Li ◽

Xia Du ◽

Xianyi Tong ◽

...

Keyword(s):

Numerical Simulation ◽

Boundary Layer ◽

Boundary Conditions ◽

Analytical Solutions ◽

Temperature Fields ◽

Dimensionless Temperature ◽

Wedge Flow ◽

Dimensionless Velocity ◽

Temperature Distributions ◽

Wall Boundary Conditions

The similarity criteria which ensure the similarity between flow and temperature fields of both the lowtemperature turbine cavity model and the actual high-temperature turbine cavity are derived and then verified using numerical simulation of two different sized rotor-stator system turbine cavities. The analytical solution of threedimensional dimensionless velocity distribution and the numerical solutions of both the three-dimensional dimensionless velocity and temperature distributions of the free disk flow field are obtained. Using these solutions as a foundation, the analytical solutions of the dimensionless temperature distribution within the boundary layer of the isothermal and nonisothermal free disk model are obtained. The numerical and analytical solutions of velocity and temperature are compared to ensure that the solutions are consistent with each other. The analytical solutions of the dimensionless velocity and temperature fields within the laminar boundary layer of the wedge flow are obtained. The approximation solutions of the dimensionless temperature of the wedge flow under subsonic speed and isothermal wall boundary conditions and the dimensionless temperature of the wedge flow under supersonic speed and adiabatic wall boundary conditions are provided. The velocity and temperature distributions of the airflow outside the strut are obtained through numerical simulation and the pattern of changes in the velocity and temperature within the laminar boundary layer of the strut is revealed. Numerical simulation on gas jet cooling and regenerative cooling for the strut are simulated and shown to be effective for thermal protection. Using a strut with rough internal surface and aviation kerosene as the cooling medium is effective at cooling. The experiment fixture used to simulate the outlet temperature of the combustor and the experimental fixture used to simulate the dynamic temperature of the compressor are designed and built. The dynamic temperature of the compressor airflow is measured using combined thermocouples. Experimental results show that the dynamic error caused by the thermal inertia of the thermocouple can be eliminated by the compensation algorithm.

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Developing mass transfer boundary layer with power law velocity profiles and wall boundary conditions

AIChE Journal ◽

10.1002/aic.690270218 ◽

1981 ◽

Vol 27 (2) ◽

pp. 298-301 ◽

Cited By ~ 1

Author(s):

F. H. Verhoff ◽

M. K. Choi

Keyword(s):

Boundary Layer ◽

Mass Transfer ◽

Boundary Conditions ◽

Power Law ◽

Velocity Profiles ◽

Wall Boundary ◽

Wall Boundary Conditions

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Ionizing argon boundary layers. Part 2. Shock-tube side-wall boundary-layer flows

Journal of Fluid Mechanics ◽

10.1017/s0022112079000409 ◽

1979 ◽

Vol 91 (4) ◽

pp. 679-696 ◽

Cited By ~ 6

Author(s):

W. S. Liu ◽

I. I. Glass

Keyword(s):

Boundary Layer ◽

Boundary Conditions ◽

Shock Tube ◽

Flat Plate ◽

Electron Number Density ◽

Side Wall ◽

Number Density ◽

Electron Number ◽

Wall Boundary ◽

Wall Boundary Conditions

A combined experimental and theoretical investigation was conducted on the shock-tube side-wall ionizing boundary-layer induced by a shock wave moving into argon. The dual-wavelength interferometric boundary-layer data were obtained by using a 23 cm diameter Mach—Zehnder interferometer with the 10 × 18 cm Hypervelocity Shock Tube at initial shock Mach numbers of 13 and 16, an initial pressure of 5 torr and a temperature of 300° K. The plasma density and electron number density in the boundary layer were measured and compared with numerical profiles obtained by using an implicit finite-difference scheme for a two-temperature, chemical non-equilibrium, laminar boundary-layer flow in ionizing argon. The analysis included the variations of transport properties based on elastic-scattering cross-sections, effects of chemical reactions, radiation-energy losses and electron-sheath wall boundary conditions. Considering the difficulties involved in such complex plasma flows, satisfactory agreement was obtained between the analyses and experiments. A comparison was made with the flat-plate case and despite the very different velocity boundary conditions at the wall for the two flows the experimental data appear to be quite similar. The experimental bump in the profile of electron number density which was found in the flat-plate case was not found in the side-wall case. Comparisons and discussions of the results for the different types of boundary layer are presented, including a comparison between experimentally derived and analytical plasma-temperature profiles.

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