Measurement of the parameters of external heat transfer by dilatometry

1977 ◽  
Vol 33 (1) ◽  
pp. 825-827
Author(s):  
V. S. Batalov ◽  
V. S. Batmanov ◽  
Yu. S. Grigor'ev ◽  
A. N. Perminov
Keyword(s):  
Heat Transfer ◽  
External Heat ◽  
External Heat Transfer

scholarly journals INFLUENCE OF SURFACE HEATING TEMPERATURE ON EXTERNAL HEAT-EXCHANGE IN WET VIBRO-FLUIDIZED BED

2018 ◽  
Vol 59 (5) ◽  
pp. 77
Author(s):  
Boris G. Sapozhnikov ◽  
Anastasiya M. Gorbunova ◽  
Yuliya O. Zelenkova ◽  
Nina P. Shiryaeva
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Heat Transfer Coefficient ◽  
Heat Exchange ◽  
Fluidized Bed ◽  
Heating Temperature ◽  
Heating Surface ◽  
External Heat ◽  
Porous Particles ◽  
External Heat Transfer

Experimental data are given on the influence of the temperature of the heating surface, placed to a wet vibro-fluidized bed of non-porous particles, and higher that the saturation temperatures on the external heat-transfer coefficient at conductive supply of the heat.

scholarly journals Effect of Discrete Surface Disturbances on Vane External Heat Transfer

1997 ◽  
Author(s):  
R. S. Bunker
Keyword(s):  
Heat Transfer ◽  
Turbulence Intensity ◽  
Pressure Ratio ◽  
Leading Edge ◽  
Suction Side ◽  
External Heat ◽  
Freestream Turbulence ◽  
External Heat Transfer ◽  
Enhancement Factors ◽  
Surface Disturbances

A transonic linear vane cascade has been utilized to assess the effects of localized surface disturbances on airfoil external heat transfer coefficient distributions, such as those which may be created by the spallation of thermal barrier coatings. The cascade operates at an overall pressure ratio of 1.86, with an inlet total pressure of about 5 atm. Cascade Reynolds numbers based on axial chord length and exit velocity range from 2.2 to 4.8 · 106. Surface disturbances are modeled with the use of narrow trip strips glued onto the surface at selected locations, such that sharp forward facing steps are presented to the boundary layer. Surface locations investigated include the near leading edge region on either side of the stagnation point, the midchord region of the pressure side, and the high curvature region of the suction side. Heat transfer enhancement factors are obtained for disturbances with engine representative height-to-momentum thickness ratios, as a function of Reynolds number. Enhancement factors are compared for both smooth and rough airfoil surfaces with added disturbances, as well as low and high freestream turbulence intensity. Results show that leading edge heat transfer is dominated by freestream turbulence intensity effects, such that enhancements of nearly 50% at low turbulence levels are reduced to about 10% at elevated turbulence levels. Both pressure and suction side enhancement factors are dominated by surface roughness caused effects, with large enhancements for smooth surfaces being drastically reduced for roughened surfaces.

An Experimental Study of Turbine Vane Heat Transfer With Leading Edge and Downstream Film Cooling

1990 ◽  
Vol 112 (3) ◽  
pp. 477-487 ◽  
Author(s):  
N. V. Nirmalan ◽  
L. D. Hylton
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Film Cooling ◽  
Pressure Ratio ◽  
Leading Edge ◽  
External Heat ◽  
Gas Temperature ◽  
Temperature Ratio ◽  
External Heat Transfer ◽  
Turbine Vane

This paper presents the effects of downstream film cooling, with and without leading edge showerhead film cooling, on turbine vane external heat transfer. Steady-state experimental measurements were made in a three-vane, linear, two-dimensional cascade. The principal independent parameters—Mach number, Reynolds number, turbulence, wall-to-gas temperature ratio, coolant-to-gas temperature ratio, and coolant-to-gas pressure ratio—were maintained over ranges consistent with actual engine conditions. The test matrix was structured to provide an assessment of the independent influence of parameters of interest, namely, exit Mach number, exit Reynolds number, coolant-to-gas temperature ratio, and coolant-to-gas pressure ratio. The vane external heat transfer data obtained in this program indicate that considerable cooling benefits can be achieved by utilizing downstream film cooling. The downstream film cooling process was shown to be a complex interaction of two competing mechanisms. The thermal dilution effect, associated with the injection of relatively cold fluid, results in a decrease in the heat transfer to the airfoil. Conversely, the turbulence augmentation, produced by the injection process, results in increased heat transfer to the airfoil. The data presented in this paper illustrate the interaction of these variables and should provide the airfoil designer and computational analyst with the information required to improve heat transfer design capabilities for film-cooled turbine airfoils.

scholarly journals Influence of marine kaolin mortar mixed with effective microorganism on external heat transfer

2020 ◽  
Vol 849 ◽  
pp. 012043
Author(s):  
F A Yusop ◽  
A Mohamed ◽  
H M Nor ◽  
A R M Sam ◽  
N H A Khalid ◽  
...  
Keyword(s):  
Heat Transfer ◽  
External Heat ◽  
External Heat Transfer ◽  
Effective Microorganism

scholarly journals Assessment of External Heat Transfer Modeling of a Laboratory-Scale Combustor Inside a Pressure-Housing Environment

2018 ◽  
Author(s):  
P. Rodrigues ◽  
O. Gicquel ◽  
N. Darabiha ◽  
K. P. Geigle ◽  
R. Vicquelin
Keyword(s):  
Heat Transfer ◽  
Cooling System ◽  
External Heat ◽  
Laboratory Scale ◽  
Radiative Properties ◽  
Temperature Fields ◽  
Transfer Model ◽  
External Heat Transfer ◽  
Heat Transfers ◽  
External Face

Many laboratory-scale combustors are equipped with viewing windows to allow for characterization of the reactive flow. Additionally, pressure housing is used in this configuration to study confined pressurized flames. Since the flame characteristics are influenced by heat losses, the prediction of wall temperature fields becomes increasingly necessary to account for conjugate heat transfer in simulations of reactive flows. For configurations similar to this one, the pressure housing makes the use of such computations difficult in the whole system. It is therefore more appropriate to model the external heat transfer beyond the first set of quartz windows. The present study deals with the derivation of such a model which accounts for convective heat transfer from quartz windows external face cooling system, free convection on the quartz windows 2, quartz windows radiative properties, radiative transfer inside the pressure housing and heat conduction through the quartz window. The presence of semi-transparent viewing windows demands additional care in describing its effects in combustor heat transfers. Because this presence is not an issue in industrial-scale combustors with opaque enclosures, it remains hitherto unaddressed in laboratory-scale combustors. After validating the model for the selected setup, the sensitivity of several modeling choices is computed. This enables a simpler expression of the external heat transfer model that can be easily implemented in coupled simulations.

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