Numerical Prediction of Wall Temperatures for Near-Critical Para-Hydrogen in Turbulent Upflow Inside Vertical Tubes

1983 ◽  
Vol 105 (3) ◽  
pp. 536-541 ◽  
Author(s):  
C. P. Bellmore ◽  
R. L. Reid
Keyword(s):  
Heat Transfer ◽  
Turbulent Transport ◽  
Density Fluctuations ◽  
Para Hydrogen ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Momentum And Heat Transfer ◽  
Turbulent Momentum ◽  
Vertical Tubes ◽  
Perturbed Equation

Presented herein is a method of including density fluctuations in the equations of turbulent transport. Results of a numerical analysis indicate that the method may be used to predict heat transfer for the case of near-critical para-hydrogen in turbulent upflow inside vertical tubes. Wall temperatures, heat transfer coefficients, and velocities obtained by coupling the equations of turbulent momentum and heat transfer with a perturbed equation of state show good agreement with experiments for inlet reduced pressures of 1.28–5.83.

Comparison of 30 Boiling and Condensation Correlations for Two-Phase Flows in Compact Plate-Fin Heat Exchangers

2017 ◽  
Author(s):  
Wenhai Li ◽  
Ken Alabi ◽  
Foluso Ladeinde
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Flow Boiling ◽  
Transfer Coefficients ◽  
Two Phase Flows ◽  
Two Phase ◽  
Heat Transfer Coefficients ◽  
Heat Exchanger Design ◽  
Micro Channels ◽  
Vertical Tubes

Over the years, empirical correlations have been developed for predicting saturated flow boiling [1–15] and condensation [16–30] heat transfer coefficients inside horizontal/vertical tubes or micro-channels. In the present work, we have examined 30 of these models, and modified many of them for use in compact plate-fin heat exchangers. However, the various correlations, which have been developed for pipes and ducts, have been modified in our work to make them applicable to extended fin surfaces. The various correlations have been used in a low-order, one-dimensional, finite-volume type numerical integration of the flow and heat transfer equations in heat exchangers. The NIST’s REFPROP database [31] is used to account for the large variations in the fluid thermo-physical properties during phase change. The numerical results are compared with Yara’s experimental data [32]. The validity of the various boiling and condensation models for a real plate-fin heat exchanger design is discussed. The results show that some of the modified boiling and condensation correlations can provide acceptable prediction of heat transfer coefficient for two-phase flows in compact plate-fin heat exchangers.

Diffusion Layer Theory for Turbulent Vapor Condensation With Noncondensable Gases

1993 ◽  
Vol 115 (4) ◽  
pp. 998-1003 ◽  
Author(s):  
P. F. Peterson ◽  
V. E. Schrock ◽  
T. Kageyama
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Mass Transfer ◽  
Vapor Condensation ◽  
Sensible Heat ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Noncondensable Gas ◽  
Noncondensable Gases ◽  
Vertical Tubes

In turbulent condensation with noncondensable gas, a thin noncondensable layer accumulates and generates a diffusional resistance to condensation and sensible heat transfer. By expressing the driving potential for mass transfer as a difference in saturation temperatures and using appropriate thermodynamic relationships, here an effective “condensation” thermal conductivity is derived. With this formulation, experimental results for vertical tubes and plates demonstrate that condensation obeys the heat and mass transfer analogy, when condensation and sensible heat transfer are considered simultaneously. The sum of the condensation and sensible heat transfer coefficients becomes infinite at small gas concentrations, and approaches the sensible heat transfer coefficient at large concentrations. The “condensation” thermal conductivity is easily applied to engineering analysis, and the theory further demonstrates that condensation on large vertical surfaces is independent of the surface height.

Turbulent Flow Friction and Heat Transfer Characteristics of Single- and Multistart Spirally Enhanced Tubes

1986 ◽  
Vol 108 (1) ◽  
pp. 55-61 ◽  
Author(s):  
R. Sethumadhavan ◽  
M. Raja Rao
Keyword(s):  
Heat Transfer ◽  
Turbulent Flow ◽  
Evaluation Criteria ◽  
Helix Angle ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Aspect Ratios ◽  
Friction Factors ◽  
Enhanced Tubes ◽  
Momentum And Heat Transfer

Investigations have been carried out on heat transfer and frictional characteristics of five spirally corrugated tubes of one to four corrugation starts, having the same helix angle, but of varying geometrical aspect ratios, for the turbulent flow of water and 50 percent glycerol. The thermal performance of these tubes was found to be superior compared to a smooth tube. Friction factors and heat transfer coefficients in these rough tubes were analysed on the basis of momentum and heat transfer analogy, and the correlation obtained was tested with the present data and also the published results of previous investigators. Performance evaluation criteria were used for the quantitative demonstration of the benefits offered by these spirally corrugated tubes for heat exchanger applications.

Heat Transfer in Gas-Solids Drag-Reducing Flow

1985 ◽  
Vol 107 (3) ◽  
pp. 570-574 ◽  
Author(s):  
R. S. Kane ◽  
R. Pfeffer
Keyword(s):  
Heat Transfer ◽  
Test Section ◽  
Particle Deposition ◽  
Reynolds Numbers ◽  
Viscous Sublayer ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Vertical Tubes ◽  
The Heat Transfer Coefficient ◽  
Vertical Test

Heat transfer coefficients of air-glass, argon-glass, and argon-aluminum suspensions were measured in horizontal and vertical tubes. The glass, 21.6 and 36.0-μ-dia particles, was suspended at gas Reynolds numbers between 11,000 and 21,000 and loading ratios between 0 and 2.5. The presence of particles generally reduced the heat transfer coefficient. The circulation of aluminum powder in. the 0.870-in.-dia closed loop system produced tenacious deposits on protuberances into the stream. In the vertical test section, the Nusselt number reduction was attributed to viscous sublayer thickening; in the horizontal test section to particle deposition.

Sign in / Sign up

Export Citation Format

Share Document