Sea Water Distillatory Using Rising Film on the Fluted Surface of Horizontal Tubes

2006 ◽  
Author(s):  
Yan Li ◽  
Ning Mei ◽  
Yesheng Sun
Keyword(s):  
Thin Film ◽  
Heat Transfer ◽  
Theoretical Analysis ◽  
Numerical Solution ◽  
Temperature Difference ◽  
Sea Water ◽  
Flow Characteristics ◽  
Horizontal Tube ◽  
Transfer Model ◽  
Horizontal Tubes

The purpose of this study is to investigate the mechanism of the seawater distillatory using rising liquid thin film on the fluted surface of a horizontal tube. By analyzing the formation of the rising film, a process of the HRF evaporators was designed to analysis the efficiency of the system. The numerical solution of heat transfer model shows that the temperature difference of HRF in one effect is lower than that of HFF. The behaviors of the flow characteristics were discussed. The results show that the rising liquid thin film could be formed when the rate of roll equaled 15°. The results from theoretical analysis suggest that seawater distillatory using rising liquid thin film on the fluted surface of a horizontal tube was especially suitable for the wobble environment.

An Analytical Study of Laminar Film Condensation: Part 2—Single and Multiple Horizontal Tubes

1961 ◽  
Vol 83 (1) ◽  
pp. 55-60 ◽  
Author(s):  
Michael Ming Chen
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Horizontal Tube ◽  
Vertical Tube ◽  
Film Condensation ◽  
Transfer Coefficients ◽  
Inertia Effects ◽  
Horizontal Tubes ◽  
Laminar Film ◽  
Laminar Film Condensation

The boundary-layer equations for laminar film condensation are solved for (a) a single horizontal tube, and (b) a vertical bank of horizontal tubes. For the single-tube case, the inertia effects are included and the vapor is assumed to be stationary outside the vapor boundary layer. Velocity and temperature profiles are obtained for the case μvρv/μρ ≪ 1 and similarity is found to exist exactly near the top stagnation point, and approximately for the most part of the tube. Heat-transfer results computed with these similar profiles are presented and discussed. For the multiple-tube case, the analysis includes the effect of condensation between tubes, which is shown to be partly responsible for the high observed heat-transfer rate for vertical tube banks. The inertia effects are neglected due to the insufficiency of boundary-layer theory in this case. Heat-transfer coefficients are presented and compared with experiments. The theoretical results for both cases are also presented in approximate formulas for ease of application.

Application of a Complex Nusselt Number to Heat Transfer During Compression and Expansion

1994 ◽  
Vol 116 (3) ◽  
pp. 536-542 ◽  
Author(s):  
A. A. Kornhauser ◽  
J. L. Smith
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Nusselt Number ◽  
Temperature Difference ◽  
Rate Of Change ◽  
Transfer Model ◽  
Volume Data ◽  
Piston Cylinder ◽  
Compression And Expansion ◽  
Experimental Pressure

Heat transfer during compression and expansion can be out of phase with bulk gas-wall temperature difference. An ordinary convective heat transfer model is incapable of predicting this phenomenon. Expressions for compression/expansion heat transfer developed from simple conduction models use a complex heat transfer coefficient. Thus, heat flux consists of one part proportional to temperature difference plus a second part proportional to rate of change of temperature. Surface-averaged heat flux was calculated from experimental pressure-volume data for piston-cylinder gas springs over a range of speeds, pressures, gases, and geometries. The complex Nusselt number model proved capable of correlating both magnitude and phase of the measured heat transfer as functions of an oscillation Peclet number.

Flow Boiling in Horizontal Tubes: Part 3—Development of a New Heat Transfer Model Based on Flow Pattern

1998 ◽  
Vol 120 (1) ◽  
pp. 156-165 ◽  
Author(s):  
N. Kattan ◽  
J. R. Thome ◽  
D. Favrat
Keyword(s):  
Heat Transfer ◽  
Annular Flow ◽  
Flow Boiling ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Two Phase ◽  
Horizontal Tubes ◽  
High Vapor ◽  
Coefficient Versus ◽  
The Heat Transfer Coefficient

A new heat transfer model for intube flow boiling in horizontal plain tubes is proposed that incorporates the effects of local two-phase flow patterns, flow stratification, and partial dryout in annular flow. Significantly, the local peak in the heat transfer coefficient versus vapor quality can now be determined from the prediction of the location of onset of partial dryout in annular flow. The new method accurately predicts a large, new database of flow boiling data, and is particularly better than existing methods at high vapor qualities (x > 85 percent) and for stratified types of flows.

Mist/Steam Cooling in a Heated Horizontal Tube—Part 2: Results and Modeling

1999 ◽  
Vol 122 (2) ◽  
pp. 366-374 ◽  
Author(s):  
Tao Guo ◽  
Ting Wang ◽  
J. Leo Gaddis
Keyword(s):  
Heat Transfer ◽  
Wall Temperature ◽  
Experimental Studies ◽  
Local Heat Transfer ◽  
Horizontal Tube ◽  
Local Heat ◽  
Heat Fluxes ◽  
Steam Flow ◽  
Transfer Model ◽  
Steam Cooling

Experimental studies on mist/steam cooling in a heated horizontal tube have been performed. Wall temperature distributions have been measured under various main steam flow rates, droplet mass ratios, and wall heat fluxes. Generally, the heat transfer performance of steam can be significantly improved by adding mist into the main flow. An average enhancement of 100 percent with the highest local heat transfer enhancement of 200 percent is achieved with 5 percent mist. When the test section is mildly heated, an interesting wall temperature distribution is observed: The wall temperature increases first, then decreases, and finally increases again. A three-stage heat transfer model with transition boiling, unstable liquid fragment evaporation, and dry-wall mist cooling has been proposed and has shown some success in predicting the wall temperature of the mist/steam flow. The PDPA measurements have facilitated better understanding and interpreting of the droplet dynamics and heat transfer mechanisms. Furthermore, this study has shed light on how to generate appropriate droplet sizes to achieve effective droplet transportation, and has shown that it is promising to extend present results to a higher temperature and higher pressure environment. [S0889-504X(00)02502-2]

Experimental Study of Film Condensation From Steam-Air Mixtures Flowing Downward Over a Horizontal Tube

1974 ◽  
Vol 96 (1) ◽  
pp. 83-88 ◽  
Author(s):  
J. W. Rauscher ◽  
A. F. Mills ◽  
V. E. Denny
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Theoretical Analysis ◽  
Mass Fraction ◽  
Horizontal Tube ◽  
Forced Flow ◽  
Film Condensation ◽  
Air Mass ◽  
Average Value ◽  
Pure Steam

Experiments have been performed to study the effects of air on filmwise condensation from steam-air mixtures undergoing forced flow over a 3/4 in. OD horizontal tube. Local condensation rates at the stagnation point are reported for saturation temperatures of 100–150 deg F, bulk to wall temperature differences of 3–30 deg F, bulk air mass fraction 0–7 percent and oncoming vapor velocity 1–6 ft/sec. For pure steam the average value of q/qNu, where qNu is the Nusselt result, was 0.98 ± 0.10, which compares favorably with the value of 1.04 predicted by a theory which accounts for vapor drag. For steam-air mixtures the reduction in heat transfer was found to be in excellent agreement with the theoretical analysis of Denny and South; the average discrepancy in q/qNu was −2.7 percent, while the maximum was 7.1 percent.

Stratified Flow Condensation of CO2 in a Tube at Low Temperatures

2015 ◽  
Vol 789-790 ◽  
pp. 184-192
Author(s):  
Pei Hua Li ◽  
Joe Deans ◽  
Stuart Norris
Keyword(s):  
Heat Transfer ◽  
Temperature Difference ◽  
Saturation Temperature ◽  
Horizontal Tube ◽  
Stratified Flow ◽  
Heat Transfer Process ◽  
Film Condensation ◽  
Significant Feature ◽  
Transfer Coefficients ◽  
Flow Condensation

This study presents an experimental investigation of CO2flowing condensation at the saturation temperature of-10°C, mass flux in the range from 40 to 60kgm-2s-1and vapour quality ranging from 0.2 to 0.8, in a 6.52mm inside diameter horizontal tube. Previous research on refrigerant condensation has shown that under these conditions, CO2two phases are expected to develop as a stratified flow. The significant feature of the stratified flow heat transfer is vapour film condensation in the upper region which dominates the overall heat transfer process. Test series in this study confirm that the saturation-to-tube wall temperature difference has a significant influence on the condensing heat transfer coefficient when the temperature difference is within 3K. Comparisons between the experimental results and the predictions by the Dobson, Cavallini and Thome models show that CO2stratified flow condensation heat transfer coefficients are over-predicted by these models with mean deviations of 104%, 81% and 127%, respectively.

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