Experimental Investigation of Shell-Side Flow Condensation on Three-Dimensional Enhanced Surface Tubes

2020 ◽  
Author(s):  
Desong Yang ◽  
Zhichuan Sun ◽  
Wei Li
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Mass Flux ◽  
Three Dimensional ◽  
Condensation Heat Transfer ◽  
Shell Side ◽  
Plain Tube ◽  
Side Flow ◽  
The Heat Transfer Coefficient

Abstract An experimental investigation of shell-side flow condensation heat transfer was performed on advanced three-dimensional surface-enhanced tubes, including a herringbone micro-fin tube and a newly-developed 1-EHT tube. An equivalent plain tube was also tested for performance comparison. All of the test tubes have similar geometry parameters (inner diameter 11.43mm, outer diameter 12.7mm). Tests were conducted using R410A as the working fluid at a condensation saturation temperature of 45 °C, covering the mass flux range of 10–55 kg/(m2·s) with an inlet quality of 0.8 and an outlet quality of 0.1. Experimental results showed that the plain tube exhibits a better condensation heat transfer performance when compared to the enhanced tubes. Moreover, the mass flux has a significant influence on the heat transfer coefficient for shell-side condensation: the condensation heat transfer coefficient of plain tube decreases when the refrigerant mass flux becomes larger, while the heat transfer coefficient of herringbone tube shows a non-monotonic trend and the heat transfer coefficient of the 1-EHT tube gets higher with increasing refrigerant mass flux. Besides, A new prediction model based on the Cavallini’s equation was developed to predict the condensing coefficient of the three test tubes, and the mean absolute error of the improved equations is less than 4%.

Shell-Side Flow Condensation Heat Transfer on Three-Dimensional Enhanced Surface

2021 ◽  
pp. 1-20
Author(s):  
Wei Li ◽  
Desong Yang ◽  
Jingxiang Chen ◽  
Zhichuan Sun ◽  
Jiacheng Wang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Mass Flux ◽  
Three Dimensional ◽  
Condensation Heat Transfer ◽  
Shell Side ◽  
Enhanced Tubes ◽  
Plain Tube ◽  
Flow Condensation ◽  
Side Flow

Abstract An experimental investigation of shell-side flow condensation was performed on advanced three-dimensional surface-enhanced tubes, including a herringbone micro-fin tube and a newly-developed 1-EHT tube. An equivalent plain tube was also tested for performance comparison. All the test tubes have similar geometry parameters (inner diameter 11.43mm, outer diameter 12.7mm). Tests were conducted using R410A as the working fluid at a condensation saturation temperature of 45·C, covering the mass flux range of 10-55 kg/(m2·s) with an inlet quality of 0.8 and an outlet quality of 0.1. Experimental results showed that the plain tube exhibits a better condensation heat transfer performance when compared to the enhanced tubes. Moreover, the mass flux has a significant influence on the best transfer coefficient for shell-side condensation. A new prediction model based on the Cavallini's equation was developed to predict the condensing coefficient where the mean absolute error is less than 4%.

Experimental Study on Flow Evaporation Heat Transfer Characteristics Inside Horizontal Three-Dimensional Enhanced Tubes

2018 ◽  
Author(s):  
Wei Li ◽  
Chuancai Zhang ◽  
Zhichuan Sun ◽  
Zhichun Liu ◽  
Lianxiang Ma ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Mass Flux ◽  
Three Dimensional ◽  
Outer Diameter ◽  
Evaporation Heat ◽  
Enhanced Tubes ◽  
Evaporation Heat Transfer ◽  
The Heat Transfer Coefficient

Experimental investigation was performed to measure the evaporation heat transfer coefficients of R410A inside three three-dimensional enhanced tubes (1EHT-1, 1EHT-2 and 4LB). The inner and outer enhanced surface of the 4LB tube is composed by arrays of grooves and square pits, while 1EHT-1 tube and 1EHT-2 tube consist of longitudinal ripples and dimples of different depths. All these tubes have an inner diameter of 8.32 mm and an outer diameter of 9.52 mm. Experiment operational conditions are conducted as follows: the saturation temperature is 279 K, the vapor quality ranges from 0.2 to 0.8, and the mass flux varies from 160 kg/(m2·s) to 380 kg/(m2·s). With the mass flux increasing, the heat transfer coefficient increases accordingly. The heat transfer coefficient of 1EHT-2 is the highest of all three tubes, and that of 1EHT-1 is the lowest. The heat transfer coefficient of 4LB ranks between the 1EHT-1 and 1EHT-2 tube. The reason is that the heat transfer areas of the 1EHT-2 and 4LB tube are larger than that of 1EHT-1 and interfacial turbulence is enhanced in 1EHT-2.

Investigations on the Condensation Heat Transfer Performance of Stainless Steel Edge-Shaped Finned Tubes

2015 ◽  
Vol 138 (3) ◽  
Author(s):  
Zhen-ping Wan ◽  
Xiao-wu Wang ◽  
Xiao-xia Zhang ◽  
Yong Tang
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Temperature Difference ◽  
Heat Transfer Performance ◽  
Three Dimensional ◽  
Condensation Heat Transfer ◽  
Transfer Performance ◽  
Shell Side ◽  
Finned Tubes

The third-generation enhanced heat transfer technologies, such as three-dimensional fin and dimple, are still important means of improving energy efficiency. This paper analyzes the condensation heat transfer performances of three edge-shaped finned tubes that were fabricated using the plowing–extruding process. Experimental results show that the shell-side heat transfer coefficient decreases with increases of heat flux and temperature difference between wall and vapor. The edge-shaped finned tubes exhibit better heat transfer performance than smooth tubes. At the identical temperature difference between the wall and the vapor, the shell-side heat transfer coefficient of the edge-shaped finned tubes is approximately 1.7–2.6 times larger than that of the smooth tubes. At the identical temperature difference between the wall and the vapor, the shell-side heat transfer coefficient of edge-shaped finned tubes is also higher than the reported value in the literature. The excellent performance of the edge-shaped finned tubes comes from the coordination of enhancement from the three-dimensional fins, dimples, and grooves. Finned tubes with grooves fabricated along the left direction have higher and thinner fins and therefore show better heat transfer performance. The shell-side heat transfer coefficients of edge-shaped finned tubes increase with plowing–extruding depth and feed increasing.

scholarly journals Effect of Tube Expansion on Heat Transfer and Pressure Drop Characteristics During Condensation in Micro-Fin Tubes

2021 ◽  
Vol 9 ◽  
Author(s):  
Na Liu ◽  
Qian Zhao ◽  
Zhixiang Lan
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Mass Flux ◽  
Condensation Heat Transfer ◽  
Mass Fluxes ◽  
Fin Tubes ◽  
Tube Expansion ◽  
The Heat Transfer Coefficient

Despite of the large number of research dedicated to condensation heat transfer and pressure drop characteristics in pristine micro-fin tubes, experimental investigation on effects of tube expansion have not been reported in the open literature. The paper reports measured cross-sectional dimensions, condensation heat transfer and pressure drop data of R1234ze(E) in pristine (5.10 mm OD) and expanded (5.26 mm OD) micro-fin tubes with mass fluxes from 100 to 300 kg/(m2·s). Effects of mass flux, vapor quality and tube expansion on the heat transfer coefficients and friction pressure gradients were investigated in the study. When the mass flux is 100 kg/(m2·s), the heat transfer coefficient and pressure drop of R1234ze(E) decrease after tube expansion. However, when the mass fluxes are 200 and 300 kg/(m2·s), tube expansion effects on the heat transfer coefficient and pressure drop are not notable. In addition, the experimental results are analyzed based on the existing condensation heat transfer and pressure drop correlations.

scholarly journals Comparison of Two-Equation Turbulence Models for Prediction of Heat Transfer on Film-Cooled Turbine Blades

1997 ◽  
Author(s):  
Vijay K. Garg ◽  
Ali A. Ameri
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Film Cooling ◽  
Turbine Blades ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Computer Time ◽  
Suction Surface ◽  
The Heat Transfer Coefficient

A three-dimensional Navier-Stokes code has been used to compute the heat transfer coefficient on two film-cooled turbine blades, namely the VKI rotor with six rows of cooling holes including three rows on the shower head, and the C3X vane with nine rows of holes including five rows on the shower head. Predictions of heat transfer coefficient at the blade surface using three two-equation turbulence models, specifically, Coakley’s q-ω model, Chien’s k-ε model and Wilcox’s k-ω model with Menter’s modifications, have been compared with the experimental data of Camci and Arts (1990) for the VKI rotor, and of Hylton et al. (1988) for the C3X vane along with predictions using the Baldwin-Lomax (B-L) model taken from Garg and Gaugler (1995). It is found that for the cases considered here the two-equation models predict the blade heat transfer somewhat better than the B-L model except immediately downstream of the film-cooling holes on the suction surface of the VKI rotor, and over most of the suction surface of the C3X vane. However, all two-equation models require 40% more computer core than the B-L model for solution, and while the q-ω and k-ε models need 40% more computer time than the B-L model, the k-ω model requires at least 65% more time due to slower rate of convergence. It is found that the heat transfer coefficient exhibits a strong spanwise as well as streamwise variation for both blades and all turbulence models.

Effect of Open Micro-Channels on External Condensation Heat Transfer

2016 ◽  
Author(s):  
Brandon Hulet ◽  
Andres Martinez ◽  
Melanie Derby ◽  
Amy Rachel Betz
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Film Thickness ◽  
Transfer Coefficient ◽  
Heat Fluxes ◽  
Condensation Heat Transfer ◽  
Dropwise Condensation ◽  
Micro Channels ◽  
Lower Heat ◽  
The Heat Transfer Coefficient

This research experimentally investigates the heat transfer performance of open-micro channels under filmwise condensation conditions. Filmwise condensation is an important factor in the design of steam condensers used in thermoelectric power generation, desalination, and other industrial applications. Filmwise condensation averages five times lower heat transfer coefficients than those present in dropwise condensation, and filmwise condensation is the dominant condensation regime in the steam condensers due to a lack of a durable dropwise condensation surface. Film thickness is also of concern because it is directly proportional to the condenser’s overall thermal resistance. This research focuses on optimizing the channel size to inhibit the creation of a water film and/or to reduce its overall thickness in order to maximize the heat transfer coefficient of the surface. Condensation heat transfer was measured in three square channels and a plane surface as a control. The sizes of the square fins were 0.25 mm; 0.5 mm; and 1 mm, and tests were done at a constant pressure of 6.2 kPa. At lower heat fluxes, the 0.25mm fins perform better, whereas at larger heat fluxes a smooth surface offers better performance. At lower heat fluxes, droplets are swept away by gravity before the channels are flooded. Whereas, at higher heat fluxes, the channels are flooded increasing the total film thickness, thereby reducing the heat transfer coefficient.

Experimental Study on Integrated Performance for Flower Baffle Heat Exchanger’s Distance between Two Flower Baffles

2010 ◽  
Vol 29-32 ◽  
pp. 132-137 ◽  
Author(s):  
Xue Jiang Lai ◽  
Rui Li ◽  
Yong Dai ◽  
Su Yi Huang
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
The One ◽  
Integrated Performance ◽  
Quantity Of Heat ◽  
Side Flow ◽  
The Heat Transfer Coefficient

Flower baffle heat exchanger’s structure and design idea is introduced. Flower baffle heat exchanger has unique support structure. It can both enhance the efficiency of the heat transfer and reduce the pressure drop. Through the experimental study, under the same shell side flow, the heat transfer coefficient K which the distance between two flower baffles is 134mm is higher 3%~9% than the one of which the distances between two flower baffles are 163mm,123mm. The heat transfer coefficient K which the distance between two flower baffles is 147mm is close to the one of which the distances between two flower baffles is 134mm. The shell volume flow V is higher, the incremental quantity of heat transfer coefficient K is more. The integrated performance K/Δp of flower baffle heat exchanger which the distance between two flower baffles is 134mm is higher 3%~9% than the one of which the distances between two flower baffles are 163mm,123mm. Therefore, the best distance between two flower baffles exists between 134mm~147mm this experiment.

Shell-Side Condensation Characteristics of R410A on Horizontal Enhanced Tubes

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Weiyu Tang ◽  
Wei Li
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Mass Flux ◽  
Saturation Temperature ◽  
Diffusion Resistance ◽  
Outer Diameter ◽  
Vapor Quality ◽  
Enhanced Tubes ◽  
The Heat Transfer Coefficient

Abstract An experimental investigation into heat transfer characteristics during condensation on two horizontal enhanced tubes (EHTs) was conducted. All the tested EHTs s have similar geometries with an outer diameter of 12.7 mm, and a plain tube was also tested for comparison. Investigated enhanced surfaces consist of dimples, protrusions, and grooves, which may produce more flow turbulence and enhanced the liquid drainage effect. The effects of mass fluxes and vapor quality were compared and analyzed. Test conditions were as follows: saturation temperature fixed at 45 °C, mass flux varying from 100 to 200 kg m−2 s−1, and vapor quality ranging from 0.3 to 0.8. The heat transfer coefficient was presented, and the results show that the proposed enhanced surfaces seem to have worse performance than the conventional tubes when the mass flux is less than 150 kg m−2 s−1, while one of the enhanced tubes (2EHT-1) produce an enhanced ratio of 1.03–1.14 when G = 200 kg m−2 s−1. Besides, it was found that the heat transfer coefficient increases with increasing vapor quality, which can be attributed to the increasing diffusion resistance. Mass flux seems to have little effect on the heat transfer performance of smooth tubes, while that of 1EHT increases obviously with increasing mass flux, especially for high vapor qualities.

Study on Flow Boiling Heat Transfer of Carbon Dioxide With PAG-Type Lubricating Oil in Pre-Dryout Region Inside Horizontal Tube

2010 ◽  
Author(s):  
Chaobin Dang ◽  
Minxia Li ◽  
Eiji Hihara
Keyword(s):  
Heat Transfer ◽  
Carbon Dioxide ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Mass Flux ◽  
Boiling Heat Transfer ◽  
Flow Boiling ◽  
Nucleate Boiling ◽  
Flow Boiling Heat Transfer ◽  
The Heat Transfer Coefficient

In this study, the boiling heat transfer coefficients of carbon dioxide with a PAG-type lubricating oil entrained from 0 to 5 wt% in a horizontally placed smooth tube with an inner diameter of 2 mm were experimentally investigated under the following operating conditions: mass fluxes from 170 to 320 kg/m2s, heat fluxes from 4.5 to 36 kW/m2, and a saturation temperature of 15 °C. The results show that for a low oil concentration of approximately 0.5% to 1%, no further deterioration of the heat transfer coefficient was observed at higher oil concentrations in spite of a significant decrement of the heat transfer coefficient compared to that under an oil-free condition. The heat flux still had a positive influence on the heat transfer coefficient in low quality regions. However, no obvious influence was observed in high quality regions, which implies that nucleate boiling dominates in the low quality region whereas it is suppressed in the high quality regions. Unlike the mass flux under an oil-free condition, mass flux has a significant influence on the heat transfer coefficient, with a maximum increase of 50% in the heat transfer. On the basis of our experimental measurements of the flow boiling heat transfer of carbon dioxide under wide experimental conditions, a flow boiling heat transfer model for horizontal tubes has been proposed for a mixture of CO2 and polyalkylene glycol (PAG oil) in the pre-dryout region, with consideration of the thermodynamic properties of the mixture. The surface tension and viscosity of the mixture were particularly taken into account. New factors were introduced into the correlation to reflect the suppressive effects of the mass flux and the oil on both the nucleate boiling. It is shown that the calculated results can depict the influence of the mass flux and the heat flux on both nucleate boiling and convection boiling.

Two Phase Heat Transfer of Ammonia in a Mini/Micro Channel

2010 ◽  
Author(s):  
M. Hamayun Maqbool ◽  
Bjo¨rn Palm ◽  
R. Khodabandeh ◽  
Rashid Ali
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Mass Flux ◽  
Experimental Results ◽  
Working Fluid ◽  
Internal Diameter ◽  
Vapour Quality ◽  
The Heat Transfer Coefficient

Experiments have been performed to investigate heat transfer in a circular vertical mini channel made of stainless steel (AISI 316) with internal diameter of 1.70 mm and a uniformly heated length of 245 mm using ammonia as working fluid. The experiments are conducted for a heat flux range of 15 to 350 kW/m2 and mass flux range of 100 to 500 kg/m2s. The effects of heat flux, mass flux and vapour quality on the heat transfer coefficient are explored in detail. The experimental results show that the heat transfer coefficient increases with imposed wall heat flux while mass flux and vapour quality have no considerable effect. Experimental results are compared to predictive methods available in the literature for boiling heat transfer. The correlations of Cooper et al. [1] and Shah [3] are in good agreement with our experimental data.

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