Generalization of data on convective heat transfer with vaporization to a turbulent boundary layer

1967 ◽  
Vol 13 (4) ◽  
pp. 269-271
Author(s):  
R. Sh. Vainberg
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Generalization Of Data

scholarly journals On the question of computing convective heat transfer parameters in a laminar-to-turbulent boundary layer on an impermeable hemispherical surface

2019 ◽  
pp. 17-28
Author(s):  
V.V. Gorskiy ◽  
A.G. Leonov ◽  
A.G. Loktionova
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Numerical Solutions ◽  
Turbulent Viscosity ◽  
Effective Length ◽  
Viscosity Models ◽  
Transfer Parameters

In order to qualitatively solve the problem of computing convective heat transfer parameters in a laminar-to-turbulent boundary layer, it is necessary to numerically integrate differential equations descrybing that layer, completed by semiempirical turbulent viscosity models. These must be validated using results of experimental investigations where the gas dynamics of a gas flow around a body is correctly simulated. In terms of practical applications, developing relatively simple yet highly accurate computation methods is important. At present, the most widely used method to solve this type of problems in aviation and aerospace engineering is the effective length method developed by V.S. Avduevskiy, Academician. The paper shows that significant errors characterise computations using this method and traditional turbulent viscosity models to determine parameters of those blunted components of aircraft that are subjected to the highest temperatures. We present a solution to this problem, based on constructing systematic numerical solutions to the equations describing the laminar-to-turbulent boundary layer and subsequently approximating them. We prove that this approach ensures both acceptable computation accuracy and solution simplicity.

Mechanical Augmentation of Convective Heat Transfer in Air

1975 ◽  
Vol 97 (4) ◽  
pp. 516-520 ◽  
Author(s):  
J. K. Hagge ◽  
G. H. Junkhan
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Convective Heat Transfer ◽  
Boundary Layers ◽  
Convective Heat ◽  
Convection Heat Transfer ◽  
Renewal Theory ◽  
Surface Renewal ◽  
Mechanical Removal ◽  
Blade Element

An experimental investigation was conducted into augmentation of forced convection heat transfer in air by mechanical removal of the boundary layer. A rotating blade element passing in close proximity to a flat plate convective surface was found to increase the rate of convective heat transfer by up to eleven times in certain situations. The blade element effectively scrapes away the boundary layer, thus reducing the resistance to heat flow. Parameters investigated include scraping frequency, scraper clearance, and type of boundary layer. Increased coefficients were found for higher scraping frequencies. Significant augmentation was obtained with clearance as large as 0.15 in. (0.0038 m) between the moving blade element and the convective surface. The technique appears most useful for laminar and transitional boundary layers, although some improvement was obtained for the turbulent boundary layers investigated. The simple surface renewal theory developed for scraped surface augmentation in liquids was found to approximately predict the coefficients obtained. A new relation is proposed which gives a better prediction and includes the effect of scraper clearance.

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