Computation of Surface Heat Transfer Rate on Apollo CM Test Model in Free-Piston Shock Tunnel HIEST

2012 ◽  
Author(s):  
Tomoaki Ishihara ◽  
Yousuke Ogino ◽  
Keisuke Sawada ◽  
Hideyuki Tanno
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Surface Heat ◽  
Shock Tunnel ◽  
Test Model ◽  
Free Piston ◽  
Surface Heat Transfer

New Heat Transfer Gages for Use on Multilayered Substrates

1986 ◽  
Vol 108 (1) ◽  
pp. 153-160 ◽  
Author(s):  
J. E. Doorly ◽  
M. L. G. Oldfield
Keyword(s):  
Thin Film ◽  
Heat Transfer ◽  
Wind Tunnel ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Surface Heat ◽  
Basic Flow ◽  
Surface Heat Transfer ◽  
Vitreous Enamel ◽  
Coated Metal

The paper describes a technique which enables measurements of the surface heat transfer rate to be made using thin-film gages deposited on a vitreous enamel-coated metal model. It is intended that this will have particular application in rotating turbine test rigs, where it offers considerable advantages over present techniques. These include ease of manufacture, instrumentation, durability, and lack of interference with the basic flow. The procedures for gage calibration and measurement processing are outlined, and the results of wind tunnel tests which confirm that the method is both practical and accurate are described.

scholarly journals Entropy Generation Measurement in a Laminar Turbine Blade Boundary-Layer

1997 ◽  
Author(s):  
John D. Wallace ◽  
Mark R. D. Davies
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Heat Transfer Rate ◽  
Turbine Blade ◽  
Entropy Generation ◽  
Transfer Rate ◽  
Surface Heat ◽  
Entropy Generation Rate ◽  
Blade Surface ◽  
Surface Heat Transfer

This paper demonstrates a method of calculating the entropy generation rate in an incompressible laminar turbine blade boundary-layer from measurements of surface heat transfer rate. It is shown that the entropy generated by fluid friction in an incompressible blade boundary-layer is significantly less than that generated by heat transfer at engine representative temperature ratios. The centre blade in a low-speed linear cascade is electrically heated and isolated from the airflow with a bypass valve. Upon opening the valve the blade is transiently cooled and thin film heat transfer gauges, painted on machinable glass ceramic inserts mounted into the surface of the blade, are used to record blade surface temperature and surface heat transfer rate signals; local Nusselt numbers are then calculated. Non-dimensional temperature distributions are derived across the boundary-layer using the blade surface heat transfer rate and a similarity condition. The equation describing the local entropy generation per unit volume is then integrated through the boundary-layer at each chordwise measurement point on the blade surface.

Non-similar solutions for mixed convection along a wedge embedded in a porous medium saturated by a non-Newtonian nanofluid

2014 ◽  
Vol 24 (7) ◽  
pp. 1471-1486 ◽  
Author(s):  
Ali J. Chamkha ◽  
M. Rashad ◽  
Rama Subba Reddy Gorla
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Friction Factor ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Mass Transfer Rate ◽  
Surface Heat ◽  
Content Type ◽  
Transfer Rates ◽  
Surface Heat Transfer

Purpose – The purpose of this paper is to present a boundary layer analysis for the mixed convection past a vertical wedge in a porous medium saturated with a power law type non-Newtonian nanofluid. Numerical results for friction factor, surface heat transfer rate and mass transfer rate have been presented for parametric variations of the buoyancy ratio parameter Nr, Brownian motion parameter Nb, thermophoresis parameter Nt, Lewis number Le and the power law exponent n. The dependency of the friction factor, surface heat transfer rate (Nusselt number) and mass transfer rate on these parameters has been discussed. Design/methodology/approach – This general non-linear problem cannot be solved in closed form and, therefore, a numerical solution is necessary to describe the physics of the problem. An implicit, tri-diagonal finite-difference method has proven to be adequate and sufficiently accurate for the solution of this kind of problems. Therefore, it is adopted in the present study. Variable step sizes were used. The convergence criterion employed in this study is based on the difference between the current and the previous iterations. When this difference reached 10−5 for all the points in the η directions, the solution was assumed to be converged, and the iteration process was terminated. Findings – The results indicate that as the buoyancy ratio parameter (Nr) and thermophoresis parameter (Nt) increase, the friction factor increases whereas the heat transfer rate (Nusselt number) and mass transfer rate (Sherwood number) decrease. As the Brownian motion parameter (Nb) increases, the friction factor and surface mass transfer rates increase whereas the surface heat transfer rate decreases. As Le increases, mass transfer rates increase. As the power law exponent n increases, the heat and mass transfer rates increase. Research limitations/implications – The analysis is valid for natural convection dominated regime. The combined forced and natural convection dominated regimes will be reported in a future work. Practical implications – The approach used is useful in optimizing the porous media heat transfer problems in geothermal energy recovery, crude oil extraction, ground water pollution, thermal energy storage and flow through filtering media. Originality/value – The results of the study may be of some interest to the researchers of the field of porous media heat transfer. Porous foam and microchannel heat sinks used for electronic cooling are optimized utilizing the porous medium. The utilization of nanofluids for cooling of microchannel heat sinks requires understanding of fundamentals of nanofluid convection in porous media.

Instantaneous Local Heat Flux Measurements in a Small Utility Engine

2009 ◽  
Author(s):  
Terry Hendricks ◽  
Jaal Ghandhi ◽  
John Brossman
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Numerical Model ◽  
Surface Temperature ◽  
Heat Transfer Rate ◽  
Surface Heat Flux ◽  
Transfer Rate ◽  
Surface Heat ◽  
High Load ◽  
Flux Measurements

Heat flux measurements were performed in an air-cooled utility engine using a fast-response coaxial-type surface thermocouple. The surface heat flux was calculated using both analytical and numerical models. The heat flux was found to be a strong function of engine load. The peak heat flux and initial heat flux rise rate increase with engine load. The measured heat flux data were used to estimate a global heat transfer rate, and this was compared with the heat transfer rate calculated by a single-zone heat release analysis. The measured values of heat transfer were higher than the calculated values largely because of the lack of spatial averaging. The high load data showed an unexplainable negative heat flux during the expansion stroke while the gas temperature was still high. A 1D and 2D finite difference numerical model utilizing an adaptive timestep Crank-Nicholson (CN) integration routine was developed to investigate the surface temperature measurement. Applying the measured surface temperature profile to the 1D model, the resultant surface heat flux showed excellent agreement with the analytical inversion solution and captured the reversal of the energy flow back into the cylinder during the expansion stroke. The 2D numerical model was developed to observe transient lateral conduction effects within the probe and incorporated the various materials used in the construction and assembly of the heat flux sensor. The resulting average heat flux profile for the test case is shown to be slightly higher in peak and longer in duration when compared with the results from the 1D analytical inversion, and this is attributed to contributions from the high thermal diffusivity constituents in the sensor. Furthermore, the negative heat flux at high load was not eliminated suggesting that factors other than lateral conduction may be affecting the measurement accuracy.

Convective heat-transfer rate and surface pressure distribution over a cone model at hypersonic speeds

2018 ◽  
Vol 233 (10) ◽  
pp. 3649-3664
Author(s):  
M Saiprakash ◽  
C SenthilKumar ◽  
G Balu ◽  
V Shanmugam ◽  
Singh Prakash Rampratap ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Pressure Distribution ◽  
Heat Transfer Rate ◽  
Surface Pressure ◽  
Transfer Rate ◽  
Shock Tunnel ◽  
Surface Pressure Distribution ◽  
Cone Model ◽  
Hypersonic Shock ◽  
Hypersonic Shock Tunnel

In this article, experiments are carried out in a hypersonic shock tunnel with helium as driver gas and air as the test gas to obtain the convective heating rate and surface pressure distribution on a cone model placed at hypersonic speed. Test is performed in hypersonic shock tunnel for a flow Mach number of 6.5 at two different angles of attack, 0° and 5°. The sputtered thin film platinum sensors are used to measure the heat flux on a cone model. The measured heat-transfer rate compares well with theoretically estimated values using reference enthalpy method and computational fluid dynamics (CFD) simulation. The measured surface pressure compares well with CFD.

Measurement of Heat-Transfer Rate to a Gas Turbine Stator

1979 ◽  
Vol 101 (2) ◽  
pp. 275-280 ◽  
Author(s):  
M. G. Dunn ◽  
F. J. Stoddard
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Test Section ◽  
Transfer Rate ◽  
Shock Tunnel ◽  
Pressure Losses ◽  
Turbine Stator ◽  
Experimental Apparatus ◽  
Film Heat Transfer ◽  
Intake Flow

A sector of the first stage stationary inlet nozzle of the AiResearch TFE-731-2 engine was instrumented with thin-film heat-transfer gages and experiments were performed to obtain detailed heat-transfer rate distributions. It is shown that the experimental apparatus can be used to study total-pressure losses in cascades. The experimental apparatus consists of a helium-driven shock tube, as a short-duration source of high-temperature high-pressure gas, driving a nozzle-test-section mounted near the exit of a primary shock-tunnel nozzle and extending into the shock-tunnel receiver tank. The nozzle-test-section device consists of a forward transition section with a circular opening facing the supersonic primary nozzle flow and with the external shape of a frustum of a cone. Internal contouring is provided to transform the circular-section subsonic intake flow into one filling a 176 deg annular segment having a geometry approximating that of the entrance to the turbine stator stage in a turbojet.

High Temperature Endurance of FRP Composites With Polymeric Thermal Barrier Coatings

2010 ◽  
Author(s):  
Edwin Igiede ◽  
Patrick F. Mensah ◽  
Stephen Akwaboa
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
High Temperature ◽  
Internal Energy ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Surface Heat ◽  
External Boundary ◽  
Temperature Dependent ◽  
Composite Pipe

High Temperature exposure and the corresponding thermo-mechanical behavior of cylindrical polymer composite pipe using CFD simulation has been investigated in this study. The software FLUENT was employed for the analysis of heat transfer, by coupling equations of energy and motion. Analysis was done based on applied external boundary temperature profile, change in internal energy, the total surface heat flux and surface heat transfer rate in order to evaluate the extent of thermal damage. FLUENT compatible program written in C++ language in the form of user define functions (UDF) has been developed and used to specify the time dependent heat flux generated temperature as well as temperature dependent thermal properties of density, thermal conductivity and specific heat. Available furnace test experimental data from (ASTM 1173-95) database were used as outer surface boundary condition in the model setup by developing it into UDF correlation equations. The outputs of the FLUENT simulations are predictions of transient temperature distribution through the thickness of the pipe wall that were then used in evaluating the thermal stresses of the composite pipe. Validation of the simulation results is done with existing data available in the literature. Using the wall generated temperatures, internal energy, the rate of change of the temperature dependent properties and the heat transfer rate, the thermal endurance of each of the coatings materials has been predicted in this work. At the same time knowledge of the thermal performance of these materials is essential for the optimum design of protection based on the composite application.

Procedures for Determining Surface Heat Flux Using Thin Film Gages on a Coated Metal Model in a Transient Test Facility

1988 ◽  
Vol 110 (2) ◽  
pp. 242-250 ◽  
Author(s):  
J. E. Doorly
Keyword(s):  
Thin Film ◽  
Heat Transfer ◽  
Heat Flux ◽  
Heat Transfer Rate ◽  
Surface Heat Flux ◽  
Transfer Rate ◽  
Turbine Blades ◽  
Surface Heat ◽  
Test Facility ◽  
Coated Metal

The paper describes how thin film surface heat flux gages may be used to measure surface heat transfer rate to enamel-coated metal turbine blades. Flexible methods, which are also computationally efficient, for obtaining the heat transfer rate are described. Experimental results, using the new coated metal turbine blades and processing techniques, in a stationary transient cascade facility are given, and are shown to agree well with results using the existing method for gages on single-layer substrate blades. The application of the gages for measuring highly unsteady heat transfer is also discussed.

Natural Convective Boundary-Layer Flow Over a Vertical Cylinder Embedded in a Porous Medium Saturated With a Nanofluid

2012 ◽  
Vol 3 (3) ◽  
Author(s):  
Rama Subba Reddy Gorla ◽  
Waqar Khan
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Mass Transfer ◽  
Porous Medium ◽  
Friction Factor ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Mass Transfer Rate ◽  
Vertical Cylinder ◽  
Surface Heat

In this paper, a boundary layer analysis is presented for the natural convection past a vertical cylinder in a porous medium saturated with a nanofluid. Numerical results for friction factor, surface heat transfer rate, and mass transfer rate have been presented for parametric variations of the buoyancy ratio parameter Nr, Brownian motion parameter Nb, thermophoresis parameter Nt, and Lewis number Le. The dependency of the friction factor, surface heat transfer rate (Nusselt number), and mass transfer rate on these parameters has been discussed. The results indicate that as Nr, Nb, and Nt increase, the friction factor and heat transfer rate (Nusselt number) decrease. The mass transfer rate (Sherwood number) increases with Le, Nb, and Nt.

Surface Heat Transfer Measurements of a Scaled Rib-Roughened Serpentine Cooling Passage by Use of a Transient Liquid Crystal Technique

1998 ◽  
Author(s):  
Ken-ichi Funazaki ◽  
Kouhei Ishizawa ◽  
Shigemichi Yamawaki
Keyword(s):  
Heat Transfer ◽  
Liquid Crystal ◽  
Surface Heat ◽  
Bulk Temperature ◽  
Test Model ◽  
Thermochromic Liquid Crystal ◽  
Scaled Model ◽  
Surface Heat Transfer ◽  
Cooling Passage ◽  
Straight Duct

This study is aimed at providing heat transfer characteristics of the three-pass turbulated serpentine cooling channel inside a 10:1 scaled model of an actual turbine blade. A transient method using Thermochromic Liquid Crystal (TLC) is employed to measure the surface heat transfer distribution inside the model. Great attention is paid to the streamwise decrease in the mainstream temperature due to the heat absorption into the test model. To overcome this problem, the present study employed the linear interpolating method used by Ekkad and Han (1997) to estimate the local air bulk temperature. The soundness of the measuring method is verified through the heat transfer measurements of straight-duct models with and without turbulence promoting ribs. It follows from the heat transfer measurement of the serpentine model, in conjunction with the flow visualization, that the geometries of the cross-section of the cooling passage influence the flow pattern, resulting in substantial change in heat transfer distribution in the serpentine model in comparison with that of the straight-duct model.

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