AN EXPERIMENTAL-NUMERICAL METHOD OF INVESTIGATION OF FALLING-FILM HEAT TRANSFER ON A HORIZONTAL TUBE WITH NONUNIFORM HEAT FLUX

1990 ◽  
Author(s):  
V. Przulj ◽  
E. N. Ganic
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Numerical Method ◽  
Horizontal Tube ◽  
Falling Film ◽  
Film Heat Transfer

Investigation on Intertube Falling-Film Heat Transfer and Mode Transitions of Aqueous-Alumina Nanofluids

2011 ◽  
Vol 133 (5) ◽  
Author(s):  
Binglu Ruan ◽  
Anthony M. Jacobi
Keyword(s):  
Heat Transfer ◽  
Horizontal Tube ◽  
Sodium Dodecylbenzene Sulfonate ◽  
Falling Film ◽  
Dodecylbenzene Sulfonate ◽  
Reynolds Number Increase ◽  
New Type ◽  
Aqueous Aluminum ◽  
Mode Transitions ◽  
Film Heat Transfer

Horizontal-tube falling-film heat transfer characteristics of aqueous aluminum oxide nanofluids at concentrations of 0 vol %, 0.05 vol %(0.20 wt %), 0.5 vol %(1.96 wt %), 1 vol %(3.86 wt %) (with and without sodium dodecylbenzene sulfonate), and 2 vol %(7.51 wt %) are investigated and compared with predictions developed for conventional fluids. The thermophysical properties of the nanofluids, including thermal conductivity, kinematic viscosity, and surface tension, are reported, as is the mode transition behavior of the nanofluids. The experimental results for heat transfer are in good agreement with predictions for falling-film flow and no unusual Nu enhancement was observed in the present studies. Additionally, a 20% mode transitional Reynolds number increase was recorded for transitions between sheets and jets and jet-droplet mode to droplet mode. Although the findings with water-alumina nanofluids are not encouraging with respect to heat transfer, the results extend nanofluid data to a new type of flow and may help improve our understanding of nanofluid behavior. Moreover, this work provides a basis for further work on falling-film nanofluids.

Falling film heat transfer analysis on a bank of horizontal tube evaporator

AIChE Journal ◽  
1988 ◽  
Vol 34 (9) ◽  
pp. 1539-1549 ◽  
Author(s):  
G. Kocamustafaogullari ◽  
I. Y. Chen
Keyword(s):  
Heat Transfer ◽  
Horizontal Tube ◽  
Heat Transfer Analysis ◽  
Falling Film ◽  
Film Heat Transfer

scholarly journals Heat Transfer Enhancement of Falling Film Evaporation on a Horizontal Tube by Thermal Spray Coating

2020 ◽  
Vol 10 (5) ◽  
pp. 1632 ◽  
Author(s):  
Tsutomu Ubara ◽  
Hitoshi Asano ◽  
Katsumi Sugimoto
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Transfer Enhancement ◽  
Spray Coating ◽  
Horizontal Tube ◽  
Thermal Spray Coating ◽  
Falling Film ◽  
Transfer Enhancement ◽  
Film Evaporation ◽  
Falling Film Evaporation

Falling film evaporators are gaining popularity as substitutes to typical flooded evaporators because of their low refrigerant charge. It is important to form and keep a thin liquid film on the heat transfer surface to ensure their high heat transfer performance. In this study, as a heat transfer enhancement surface, a fine porous surface processed using thermal spray coating was applied to a smooth copper tube with an outer diameter of 19.05 mm. Heat transfer coefficients of falling film evaporation on a single horizontal tube were experimentally evaluated using the HFC-134a refrigerant. The experiments were performed at a saturation temperature of 20 °C with the heat flux ranging from 10 to 85 kW·m−2 and for film Reynolds numbers up to 673. The study aimed to clarify the effect of the coating on the heat transfer characteristics of falling film evaporation. The results revealed that the coating could suppress partial dry out and enhance nucleate boiling in the falling film. The maximum heat transfer enhancement factor was 5.2 in the experimental range. It was further noted that the effect of the coating was especially strong under a low heat flux condition.

Numerical Simulation of the Liquid Flowing and Heat-Transfer outside the Tube of the Horizontal-Tube Falling Film Evaporator

2012 ◽  
Vol 614-615 ◽  
pp. 296-300 ◽  
Author(s):  
Wei Kang Hu ◽  
Li Yang ◽  
Lei Hong Guo
Keyword(s):  
Heat Transfer ◽  
Horizontal Tube ◽  
Water Desalination ◽  
Falling Film ◽  
Transfer Enhancement ◽  
Film Evaporation ◽  
Film Evaporator ◽  
Spray Density ◽  
Performance Of Heat Transfer ◽  
Falling Film Evaporation

This paper mainly studies the falling film evaporator in the field of water desalination. Using the method of fluent simulates the process of the liquid flowing and heat-transfer on the horizontal-tube falling film evaporation. The author analyses the distribution of the liquid film, and obtain the rule that spray density, evaporation temperature, temperature difference and pipe diameter affect the performance of heat-transfer in a certain range. So the paper plays a guiding role in heat transfer enhancement in the falling film evaporator.

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