Laminar convective heat-transfer rates on a hemisphere cylinder in rarefied hypersonic flow

AIAA Journal ◽  
1971 ◽  
Vol 9 (8) ◽  
pp. 1661-1663 ◽  
Author(s):  
DAVID E. BOYLAN
Keyword(s):  
Heat Transfer ◽  
Convective Heat Transfer ◽  
Hypersonic Flow ◽  
Convective Heat ◽  
Transfer Rates

APPLICATION OF ADSORPTION METHOD FOR DETERMINATION OF LOCAL CONVECTIVE HEAT TRANSFER RATES

1974 ◽  
Author(s):  
S. Koncar-Djurdjevic ◽  
M. Mitrovic ◽  
S. Cvijovic ◽  
G. Popovic ◽  
Dimitrije Voronjec
Keyword(s):  
Heat Transfer ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Adsorption Method ◽  
Transfer Rates

Influence of Short Helical Tape on Local Convective Heat Transfer and Thermal Performance Characteristics in Turbulent Decaying Swirl Flow

2010 ◽  
Vol 8 (1) ◽  
Author(s):  
Smith Eiamsa-ard ◽  
Vichan Kongkaitpaiboon ◽  
Khwanchit Wongcharee
Keyword(s):  
Heat Transfer ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Thermal Performance ◽  
Swirl Flow ◽  
Transfer Rates ◽  
Friction Factors ◽  
Plain Tube ◽  
Uniform Wall ◽  
Uniform Wall Heat Flux

This paper reports the experimental investigation of local convective heat transfer enhancement, flow friction and thermal performance factor behaviors in the tube fitted with the short helical tapes (SHTs) acting as decaying swirl flow generators. The tapes with three different helical tape angles (? = 90°, 135° and 180°) and three different channel numbers (N = 2, 3 and 4 channels) were tested under the uniform wall heat flux condition. The performance of each tape is compared with the performance of the plain tube subject to the same pumping power. The experimental results show that the heat transfer rates and friction factors of the tube with SHTs are respectively in range of 1.15 to 1.9 and 1.49 to 2.31 times of those in the plain, corresponding to thermal performances between 0.98 and 1.46. The correlations for Nusselt number (Nu) as a function of Reynolds number (Re), Prandtl number (Pr), helical tape angle (?) and the number of channel (N) are also developed.

Gas Turbimes for High-Specific-Output Industrial Heat-Transfer Equipment

1972 ◽  
Vol 186 (1) ◽  
pp. 205-220
Author(s):  
E. Kellett
Keyword(s):  
Heat Transfer ◽  
Convective Heat Transfer ◽  
Gas Turbine ◽  
Convective Heat ◽  
Gas Turbines ◽  
Low Cost ◽  
Heat Transfer Fluid ◽  
Transfer Rates ◽  
High Heat Transfer ◽  
Pressurized Combustion

The incompatibility of the dual role of air as a combustion and heat-transfer fluid is apparent in the unbalance of convective heat transfer in a water boiler. Pressurized combustion has, since the middle of the nineteenth century, been postulated as a means of increasing the gas-side convective heat transfer to more nearly correspond with the water-side rate. Gas turbines, in the form of turbine-driven supercharged boilers, have been made, but without significant commercial success, in Europe and America. Modern gas turbines are employed in total-energy systems but because of the premium value of their shaft power output, additional heat exchangers must have the minimum pressure loss and therefore conventional heat-transfer criteria apply. Small turbine-driven superchargers are now mass produced for automotive diesel engines and particularly with the availability of natural gas the feasibility of pressurized combustion by their use justifies re-appraisal. Although these turbochargers have little value as gas-turbine power units the margin of turbine output over compressor power absorption can be employed to improve heat-exchanger convective heat-transfer rates significantly. The provision of a second compressor in the rotor system enables a stoichiometric air and gaseous fuel charge to be induced into a simple pre-mixed combustor thus preserving the low-cost aspect of the turbocharger and providing improved control and safety in a very durable gas-turbine device. The addition of a simple after-burner allows total combustion at relatively low excess air rates. The arguments leading to the foregoing design are presented and some of the more important product developments are described. Examination of the wider application potential of such low-cost turbomachinery indicates prospects for their employment in diverse uses particularly where high heat-transfer rates are desirable.

Natural Convective Heat Transfer Rates During the Solidification and Melting of Metals and Alloy Systems

1974 ◽  
Vol 96 (3) ◽  
pp. 377-384 ◽  
Author(s):  
F. M. Chiesa ◽  
R. I. L. Guthrie
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Heat Transfer Correlation ◽  
Transient Conditions ◽  
Steady State Analysis ◽  
Tin Alloys ◽  
Transfer Rates ◽  
Dendritic Alloy

Analysis of experiments involving a cylindrical column of lead in the process of freezing downward or alternatively, of melting upward from the base of the container, showed that heat transfer rates associated with Be´nard convection are less under transient conditions than at steady-state. Analysis of experiments involving the freezing of lead-tin alloys (0.2 – 1.6 wt. percent Sn) showed that the same heat transfer correlation for Be´nard convection could be applied, provided the upper bounding “interface” was located on the solidus isotherm for planar and cellular alloy growth, and on the liquidus, for cellular-dendritic alloy growth.

Radiative and convective heat transfer in hypersonic flow around a blunt body

1972 ◽  
Vol 7 (5) ◽  
pp. 800-809 ◽  
Author(s):  
L. M. Biberman ◽  
S. Ya. Bronin ◽  
A. N. Lagar'kov
Keyword(s):  
Heat Transfer ◽  
Convective Heat Transfer ◽  
Hypersonic Flow ◽  
Convective Heat ◽  
Blunt Body

Effect of Periodic Flow Structure on Heat Transfer in Milliscale Confined Impinging Newtonian and Non-Newtonian Flow

2018 ◽  
Author(s):  
Ajay Chatterjee ◽  
Drazen Fabris
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Convective Heat Transfer ◽  
Steady Flow ◽  
Convective Heat ◽  
Relative Length ◽  
Periodic Flow ◽  
Transfer Rates ◽  
Flow And Heat Transfer ◽  
Parallel Surfaces

Impinging flows are widely used to enhance convective heat transfer by promoting separation, recirculation and higher rates of local convection. We consider unsteady flow and heat transfer effects in a prototypical T-shaped geometry as an impinging jet. Depending on the relative length scales, the steady laminar flow in this geometry may lose stability and transition to time periodic flow even at a low Reynolds number. A key feature of the periodic structure is the presence of ‘twin’ circulation regions adjacent to the jet column, and separation vortices anchored at the impinging surface in place of the wall jet in steady flow. The separation vortices are located above shear layers lying along the confining plane of the geometry which is flush with the jet exit. Consequently, convective heat transfer is enhanced across this plane. We present calculations to show the effect of the structure of the periodic flow on heat transfer rates across the two parallel surfaces. For a shear thinning fluid the local Nusselt number at the confining surface averaged over a long length scale (∼ 50 times the nozzle width) is more than twice as large compared to that in steady flow, while for the Newtonian fluid the mean Nusselt number increases about 60%. A mild increase in the transport rate across the impinging surface is also observed. Thus flow periodicity due to instability of the steady flow field provides a mechanism to increase the total heat transfer rate across the two surfaces.

scholarly journals Empirical mapping of the convective heat transfer coefficients with local hot spots on highly conductive surfaces

2017 ◽  
Vol 21 (3) ◽  
pp. 1231-1240
Author(s):  
Murat Tekelioğlu
Keyword(s):  
Heat Transfer ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Hot Spots ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Transfer Coefficients ◽  
Transfer Rates ◽  
Heat Transfer Coefficients ◽  
Convective Heat Transfer Coefficients

An experimental method was proposed to assess the natural and forced convective heat transfer coefficients on highly conductive bodies. Experiments were performed at air velocities of 0m/s, 4.0m/s, and 5.4m/s, and comparisons were made between the current results and available literature. These experiments were extended to arbitrary-shape bodies. External flow conditions were maintained throughout. In the proposed method, in determination of the surface convective heat transfer coefficients, flow condition is immaterial, i.e., either laminar or turbulent. With the present method, it was aimed to acquire the local heat transfer coefficients on any arbitrary conductive shape. This method was intended to be implemented by the heat transfer engineer to identify the local heat transfer rates with local hot spots. Finally, after analyzing the proposed experimental results, appropriate decisions can be made to control the amount of the convective heat transfer off the surface. Limited mass transport was quantified on the cooled plate.

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