Experimental Investigation of Combined Forced and Free Laminar Convection in Horizontal Tubes

1975 ◽  
Vol 97 (2) ◽  
pp. 212-219 ◽  
Author(s):  
S. M. Morcos ◽  
A. E. Bergles
Keyword(s):  
Heat Transfer ◽  
Rayleigh Number ◽  
Tube Wall ◽  
Steel Tubes ◽  
Fully Developed Flow ◽  
Transfer Data ◽  
Horizontal Tubes ◽  
Flow Heat ◽  
Laminar Convection ◽  
Heated Glass

The present study considers the effects of property variations on fully developed laminar flow heat transfer and pressure drop in horizontal tubes. A facility was developed to test electrically heated glass and stainless steel tubes, with distilled water and ethylene glycol as working fluids. The Nusselt number for fully developed flow depends primarily on Rayleigh number; however, the Prandtl number and a dimensionless tube wall parameter are also required to correlate the four sets of heat transfer data. This correlation agrees well with data of most previous investigations. The friction factor increases with increasing Rayleigh number; data are within the bounds of limiting analytical predictions.

Heat Transfer Measurements for the Horizontal Micro-Tubes Using Liquid Crystal Thermography

2013 ◽  
Vol 816-817 ◽  
pp. 166-169 ◽  
Author(s):  
C.H. Lam ◽  
L.M. Tam ◽  
H.K. Tam ◽  
C.F. Kuok
Keyword(s):  
Heat Transfer ◽  
Liquid Crystal ◽  
Fully Developed Flow ◽  
Flux Boundary Condition ◽  
Experiment System ◽  
Transfer Data ◽  
Liquid Crystal Thermography ◽  
Uniform Wall ◽  
Flow Heat ◽  
Uniform Wall Heat Flux

In this study, a non-contact liquid crystal thermography (LCT) method was developed for surface temperature measurements on the micro- and micro-tubes with the diameters of 2000µm, 1000µm, 838µm and 686µm. In the single-phase heat transfer experiments, the fully-developed flow heat transfer data from laminar to turbulent regionswere obtained under the uniform wall heat flux boundary condition. The experiment system was verified with the macro-tube of 2000µm diameter tube. The results showed that buoyancy effect was not observed in the laminar region when the tube diameter was less than 1000 µm. In theturbulent region, the heat transfer data trend followed with the classical turbulent correlation. Furthermore, the current LCT results showed the similar trend when compare with the published LCT data of Yang and Lin[1].

Effect of Wall Conduction on Combined Free and Forced Laminar Convection in Horizontal Rectangular Channels

1987 ◽  
Vol 109 (4) ◽  
pp. 936-942 ◽  
Author(s):  
G. J. Hwang ◽  
F. C. Chou
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Temperature Distribution ◽  
Finite Difference ◽  
Aspect Ratio ◽  
Finite Difference Method ◽  
Numerical Study ◽  
Fully Developed Flow ◽  
Rectangular Channels ◽  
Laminar Convection

This paper presents a numerical study of the effect of peripheral wall conduction on combined free and forced laminar convection in hydrodynamically and thermally fully developed flow in horizontal rectangular channels with uniform heat input axially, In addition to the Prandtl number, the Grashof number Gr+, and the aspect ratio γ, a parameter Kp indicating the significance of wall conduction plays an important role in heat transfer. A finite-difference method utilizing a power-law scheme is employed to solve the system of governing partial differential equations coupled with the equation for wall conduction. The numerical solution covers the parameters: Pr = 7.2 and 0.73, γ = 0.5, 1, and 2, Kp = 10−4–104, and Gr+ = 0–1.37×105. The flow patterns and isotherms, the wall temperature distribution, the friction factor, and the Nusselt number are presented. The results show a significant effect of the conduction parameter Kp.

Prediction Methods for Entry Length Heat Transfer by Combined Laminar Convection in Horizontal Tubes

1982 ◽  
Vol 196 (1) ◽  
pp. 409-415 ◽  
Author(s):  
P H G Allen ◽  
O Szpiro ◽  
M W Collins
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Laminar Flow ◽  
Prediction Methods ◽  
Entry Length ◽  
Horizontal Tubes ◽  
Temperature Distributions ◽  
Constant Rate ◽  
Full Solution ◽  
Laminar Convection

Numerical prediction methods for calculating velocity and temperature distributions in heated ducts can be made accurately but are time consuming. The paper shows possible simplifications, including the neglect of the buoyancy term, and the resultant accuracy attained. The case studied is for laminar flow, entry length heat transfer in horizontal tubes with constant rate heat flux. Comparison is made between experimental results, a full solution and an approximation based on a series of truncated versions of the fully developed temperature profile. Calculations are made both with and without variation of thermophysical properties with temperature.

The Experimental Measurement of Natural Convective Heat Transfer in Rectangular Enclosures with Concentrated Energy Sources

1980 ◽  
Vol 102 (2) ◽  
pp. 236-241 ◽  
Author(s):  
B. L. Turner ◽  
R. D. Flack
Keyword(s):  
Heat Transfer ◽  
Aspect Ratio ◽  
Experimental Measurement ◽  
Vertical Wall ◽  
Energy Sources ◽  
Transfer Rates ◽  
Transfer Data ◽  
Wollaston Prism ◽  
Theoretical Predictions ◽  
Laminar Convection

Heat transfer rates were experimentally measured for laminar convection air flows in rectangular enclosures with one isothermal heated vertical wall, a concentrated cooling strip on the opposing wall, and adiabatic top and bottom plates. Both local and overall heat transfer data were obtained by the use of a Wollaston prism schlieren interferometer. The aspect ratio of the enclosure and size and location of the cooling strip were parametrically varied for Grashof numbers of 5 × 106 to 9 × 106. Results are compared to previously available theoretical predictions for low Grashof numbers (105). Correlations are presented such that the theoretical predictions can be extended to Grashof numbers up to 107. The present data also indicate the dependence of heat transfer rates on the geometric parameters.

Post-CHF Axial- and Swirl-Flow Heat Transfer in Small Horizontal Tubes.

2005 ◽  
Vol 19 (2) ◽  
pp. 163-171 ◽  
Author(s):  
Munther M. Salim ◽  
David M. France
Keyword(s):  
Heat Transfer ◽  
Swirl Flow ◽  
Horizontal Tubes ◽  
Flow Heat

Flow Boiling in Horizontal Tubes: Part 2—New Heat Transfer Data for Five Refrigerants

1998 ◽  
Vol 120 (1) ◽  
pp. 148-155 ◽  
Author(s):  
N. Kattan ◽  
J. R. Thome ◽  
D. Favrat
Keyword(s):  
Heat Transfer ◽  
Boiling Heat Transfer ◽  
Annular Flow ◽  
Flow Boiling ◽  
Hot Water ◽  
Transfer Coefficients ◽  
Transfer Data ◽  
Heating Source ◽  
Horizontal Tubes ◽  
Flow Boiling Heat Transfer

A summary of a comprehensive experimental study on flow boiling heat transfer is presented for five refrigerants (R134a, R123, R402A, R404A, and R502) evaporating inside plain, horizontal, copper tube test sections. The test data were obtained for both 12.00 mm and 10.92 mm diameters using hot water as the heating source. Besides confirming known trends in flow boiling heat transfer data as a function of test variables, it was also proven that the heat flux level at the dryout point at the top of the tube in annular flow has a very significant downstream effect on heat transfer coefficients in the annular flow regime with partial dryout.

The Measurement of Natural Convective Heat Transfer in Triangular Enclosures

1979 ◽  
Vol 101 (4) ◽  
pp. 648-654 ◽  
Author(s):  
R. D. Flack ◽  
T. T. Konopnicki ◽  
J. H. Rooke
Keyword(s):  
Heat Transfer ◽  
Two Dimensional ◽  
Transfer Rates ◽  
Transfer Data ◽  
Rectangular Enclosure ◽  
Wollaston Prism ◽  
Flow Interactions ◽  
Side Walls ◽  
Laminar Convection ◽  
Base Width

Heat transfer rates were experimentally measured for laminar convection air flows in two-dimensional triangular enclosures with two side walls which were heated and cooled and an adiabatic bottom. Both local and overall heat transfer data were obtained by the use of a Wollaston prism schlieren interferometer. The angle between the two isothermal side walls was varied between 60 and 120 deg, which resulted in a variation in aspect ratio (enclosure height/base width) between 0.29 and 0.87, while the Grashof number was varied between 2.9 × 106 and 9.0 × 106. Results are compared to previously obtained isothermal inclined flat plate data and rectangular enclosure data. Present results agree with rectangular enclosure results. One deviation from local rectangular enclosure data was found in the apex regions of the triangular enclosures, where complex thermal and flow interactions occurred due to proximity of the two side walls.

Sign in / Sign up

Export Citation Format

Share Document