The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform
Maoqiong Gong - One of the best experts on this subject based on the ideXlab platform.
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new adiabatic and condensation two phase flow pattern maps of r14 in a Horizontal Tube
International Journal of Heat and Mass Transfer, 2018Co-Authors: Qinglu Song, Gaofei Chen, Zhiqiang Yang, Haocheng Wang, Maoqiong GongAbstract:Abstract Heat transfer and pressure drop for two-phase flow are closely related to corresponding flow patterns. In this work, an experimental investigation on adiabatic and condensation two-phase flow patterns and their transitions of tetrafluoromethane (R14) in a Horizontal Tube with inner diameter of 4 mm was conducted. Experiments were implemented at mass fluxes from 200 to 650 kg/(m2 s), saturation pressures from 1 to 3 MPa and heat fluxes from 8.2 to 28.2 kW/m2. The observed adiabatic flow patterns were compared with six well-known flow pattern maps, none of them can predict all the transition lines accurately. Therefore, a new dimensionless number S1, which takes account of inertia force, gravity force, shear force and surface tension force, was proposed to develop the new adiabatic flow pattern transition criteria. Eight groups of data were compared with the new adiabatic flow pattern map, most of the flow pattern data can be accurately predicted. What’s more, in order to explain the effect of heat flux on condensation flow pattern transitions, another new dimensionless number S2 was proposed by combining the dimensionless number S1 and boiling number together. Finally, a condensation flow pattern map was proposed based on the dimensionless number S2.
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experimental study on flow boiling heat transfer and pressure drop in a Horizontal Tube for r1234ze e versus r600a
International Journal of Refrigeration-revue Internationale Du Froid, 2018Co-Authors: Zhiqiang Yang, Gaofei Chen, Qinglu Song, Yuan Yao, Jun Shen, Maoqiong GongAbstract:Abstract This study presents flow boiling heat transfer and pressure drop characteristics of R1234ze(E) in a smooth Horizontal Tube with an inner diameter of 6 mm. The experiments were conducted at saturation pressures from 0.215 to 0.415 MPa, mass fluxes from 130 to 258 kg m−2 s−1 and heat fluxes from 10.6 to 74.8 kW m−2. The influences of saturation pressure, mass flux and heat flux were analyzed. Furthermore, the performance of R1234ze(E) was compared with R600a. The results show that heat transfer coefficient and pressure drop of R600a are larger than R1234ze(E). Several well-known correlations were evaluated and the results indicate that the correlation of Fang (2013) and Yang et al. (2017) give the best fit to the heat transfer coefficient and pressure drop respectively. Finally, a new heat transfer correlation was proposed and it makes great progress in the prediction accuracy.
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a new flow pattern map for flow boiling of r1234ze e in a Horizontal Tube
International Journal of Multiphase Flow, 2018Co-Authors: Zhiqiang Yang, Gaofei Chen, Xiaoru Zhuang, Qinglu Song, Jun Shen, Zeng Deng, Maoqiong GongAbstract:Abstract Considerable attention has recently been given to the new environment-friendly refrigerant of R1234ze(E) for applications such as heat pump and air-conditioning systems. In this study, an experiment was carried out to investigate two-phase flow patterns and flow transitions for R1234ze(E) in a smooth Horizontal Tube with an inner diameter of 6 mm. The experiments were performed at conditions covering saturation pressures from 0.215 to 0.415 MPa, mass fluxes from 130 to 258 kg/m2 s and heat fluxes from 10.6 to 74.8 kW/m2. The influences of saturation pressure, mass flux and heat flux on flow pattern transition were analyzed. Six well-known flow maps have been compared with the observed flow patterns of R1234ze(E). The results indicated that none of them can predict all the flow pattern transitions well. Thus, three dimensionless numbers K1, K2 and K3 which represent the ratio of the evaporation momentum force to the inertia force, the evaporation momentum force to the surface tension force, and the shear force to the gravity force respectively were introduced. Based on dimensionless numbers K1, K2, K3 and Xtt, a new flow pattern map for R1234ze(E) was proposed which could accurately predict the experimental data.
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experimental investigation on flow condensation heat transfer and pressure drop of r170 in a Horizontal Tube
International Journal of Refrigeration-revue Internationale Du Froid, 2016Co-Authors: Xiaoru Zhuang, Xin Zou, Maoqiong Gong, Gaofei ChenAbstract:Abstract Condensation heat transfer and pressure drop of R170 were studied experimentally in a Horizontal Tube with inner diameter of 4 mm. The tests were conducted at saturation pressures from 1 MPa to 2.5 MPa, mass fluxes from 100 kg (m2∙s)−1 to 250 kg (m2∙s)−1 and average heat fluxes from 55.3 kW m−2 to 96.3 kW m−2 over the entire vapor quality range. The effects of vapor quality, mass flux and saturation pressure on condensation heat transfer and pressure drop were examined and analyzed. The experimental data were compared with various well-known correlations of condensation heat transfer coefficient and pressure drop. The comparison results showed that Koyama et al. correlation agreed with the experimental heat transfer coefficient with a mean absolute relative deviation less than 25%, and the Yan and Lin correlation can accurately predict the experimental pressure drop with a mean absolute relative deviation less than 18%.
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two phase heat transfer and pressure drop of propane during saturated flow boiling inside a Horizontal Tube
International Journal of Refrigeration-revue Internationale Du Froid, 2014Co-Authors: Sheng Wang, Maoqiong Gong, Gaofei Chen, Zhumei SunAbstract:Abstract Comprehensive heat transfer coefficient and pressure drop data of the two-phase saturated flow boiling for propane were obtained in a smooth Horizontal Tube at conditions covering mass fluxes from 62 to 104 kg m−2 s−1, heat fluxes from 11.7 to 87.1 kW m−2, and saturated temperatures from −35.0 to −1.9 °C. Results indicate that heat transfer coefficients increase with mass and heat flux. For saturation temperature and vapor quality, distinct variation trends were observed depending on different test conditions. The heat transfer experimental data were compared with five well-known correlations. Among those, Liu–Winterton correlation shows the best agreement with a mean absolute relative deviation less than 10%. For two-phase frictional pressure gradients, the influences of saturation temperature, mass flux and vapor quality were also presented. The predicted method of Muller-Steinhagen & Heck correlation gives the best fit to the data with a mean absolute relative deviation less than 20%.
Gaofei Chen - One of the best experts on this subject based on the ideXlab platform.
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new adiabatic and condensation two phase flow pattern maps of r14 in a Horizontal Tube
International Journal of Heat and Mass Transfer, 2018Co-Authors: Qinglu Song, Gaofei Chen, Zhiqiang Yang, Haocheng Wang, Maoqiong GongAbstract:Abstract Heat transfer and pressure drop for two-phase flow are closely related to corresponding flow patterns. In this work, an experimental investigation on adiabatic and condensation two-phase flow patterns and their transitions of tetrafluoromethane (R14) in a Horizontal Tube with inner diameter of 4 mm was conducted. Experiments were implemented at mass fluxes from 200 to 650 kg/(m2 s), saturation pressures from 1 to 3 MPa and heat fluxes from 8.2 to 28.2 kW/m2. The observed adiabatic flow patterns were compared with six well-known flow pattern maps, none of them can predict all the transition lines accurately. Therefore, a new dimensionless number S1, which takes account of inertia force, gravity force, shear force and surface tension force, was proposed to develop the new adiabatic flow pattern transition criteria. Eight groups of data were compared with the new adiabatic flow pattern map, most of the flow pattern data can be accurately predicted. What’s more, in order to explain the effect of heat flux on condensation flow pattern transitions, another new dimensionless number S2 was proposed by combining the dimensionless number S1 and boiling number together. Finally, a condensation flow pattern map was proposed based on the dimensionless number S2.
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experimental study on flow boiling heat transfer and pressure drop in a Horizontal Tube for r1234ze e versus r600a
International Journal of Refrigeration-revue Internationale Du Froid, 2018Co-Authors: Zhiqiang Yang, Gaofei Chen, Qinglu Song, Yuan Yao, Jun Shen, Maoqiong GongAbstract:Abstract This study presents flow boiling heat transfer and pressure drop characteristics of R1234ze(E) in a smooth Horizontal Tube with an inner diameter of 6 mm. The experiments were conducted at saturation pressures from 0.215 to 0.415 MPa, mass fluxes from 130 to 258 kg m−2 s−1 and heat fluxes from 10.6 to 74.8 kW m−2. The influences of saturation pressure, mass flux and heat flux were analyzed. Furthermore, the performance of R1234ze(E) was compared with R600a. The results show that heat transfer coefficient and pressure drop of R600a are larger than R1234ze(E). Several well-known correlations were evaluated and the results indicate that the correlation of Fang (2013) and Yang et al. (2017) give the best fit to the heat transfer coefficient and pressure drop respectively. Finally, a new heat transfer correlation was proposed and it makes great progress in the prediction accuracy.
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a new flow pattern map for flow boiling of r1234ze e in a Horizontal Tube
International Journal of Multiphase Flow, 2018Co-Authors: Zhiqiang Yang, Gaofei Chen, Xiaoru Zhuang, Qinglu Song, Jun Shen, Zeng Deng, Maoqiong GongAbstract:Abstract Considerable attention has recently been given to the new environment-friendly refrigerant of R1234ze(E) for applications such as heat pump and air-conditioning systems. In this study, an experiment was carried out to investigate two-phase flow patterns and flow transitions for R1234ze(E) in a smooth Horizontal Tube with an inner diameter of 6 mm. The experiments were performed at conditions covering saturation pressures from 0.215 to 0.415 MPa, mass fluxes from 130 to 258 kg/m2 s and heat fluxes from 10.6 to 74.8 kW/m2. The influences of saturation pressure, mass flux and heat flux on flow pattern transition were analyzed. Six well-known flow maps have been compared with the observed flow patterns of R1234ze(E). The results indicated that none of them can predict all the flow pattern transitions well. Thus, three dimensionless numbers K1, K2 and K3 which represent the ratio of the evaporation momentum force to the inertia force, the evaporation momentum force to the surface tension force, and the shear force to the gravity force respectively were introduced. Based on dimensionless numbers K1, K2, K3 and Xtt, a new flow pattern map for R1234ze(E) was proposed which could accurately predict the experimental data.
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experimental investigation on flow condensation heat transfer and pressure drop of r170 in a Horizontal Tube
International Journal of Refrigeration-revue Internationale Du Froid, 2016Co-Authors: Xiaoru Zhuang, Xin Zou, Maoqiong Gong, Gaofei ChenAbstract:Abstract Condensation heat transfer and pressure drop of R170 were studied experimentally in a Horizontal Tube with inner diameter of 4 mm. The tests were conducted at saturation pressures from 1 MPa to 2.5 MPa, mass fluxes from 100 kg (m2∙s)−1 to 250 kg (m2∙s)−1 and average heat fluxes from 55.3 kW m−2 to 96.3 kW m−2 over the entire vapor quality range. The effects of vapor quality, mass flux and saturation pressure on condensation heat transfer and pressure drop were examined and analyzed. The experimental data were compared with various well-known correlations of condensation heat transfer coefficient and pressure drop. The comparison results showed that Koyama et al. correlation agreed with the experimental heat transfer coefficient with a mean absolute relative deviation less than 25%, and the Yan and Lin correlation can accurately predict the experimental pressure drop with a mean absolute relative deviation less than 18%.
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two phase heat transfer and pressure drop of propane during saturated flow boiling inside a Horizontal Tube
International Journal of Refrigeration-revue Internationale Du Froid, 2014Co-Authors: Sheng Wang, Maoqiong Gong, Gaofei Chen, Zhumei SunAbstract:Abstract Comprehensive heat transfer coefficient and pressure drop data of the two-phase saturated flow boiling for propane were obtained in a smooth Horizontal Tube at conditions covering mass fluxes from 62 to 104 kg m−2 s−1, heat fluxes from 11.7 to 87.1 kW m−2, and saturated temperatures from −35.0 to −1.9 °C. Results indicate that heat transfer coefficients increase with mass and heat flux. For saturation temperature and vapor quality, distinct variation trends were observed depending on different test conditions. The heat transfer experimental data were compared with five well-known correlations. Among those, Liu–Winterton correlation shows the best agreement with a mean absolute relative deviation less than 10%. For two-phase frictional pressure gradients, the influences of saturation temperature, mass flux and vapor quality were also presented. The predicted method of Muller-Steinhagen & Heck correlation gives the best fit to the data with a mean absolute relative deviation less than 20%.
Yan Zhang - One of the best experts on this subject based on the ideXlab platform.
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experimental study on saturated flow boiling heat transfer of r170 r290 mixtures in a Horizontal Tube
International Journal of Refrigeration-revue Internationale Du Froid, 2010Co-Authors: Xin Zou, Maoqiong Gong, Gaofei Chen, Zhaohu Sun, Yan ZhangAbstract:Abstract Saturated flow boiling heat transfer coefficients in a Horizontal Tube of the binary mixtures of R170/R290 were measured. The experiments were performed at three different mixture compositions and various saturation pressures from 0.35 to 0.57 MPa. The results were obtained over the mass fluxes ranging from 63.6 to 102.5 kg m−2 s−1 and heat fluxes ranging from 13.1 to 65.5 kW m−2. The influences of quality, saturation pressure, heat flux and mass flux on the heat transfer characteristic were examined and discussed. The flow pattern of mixture was shown and the transitions of flow pattern occur at higher mass flux and quality for mixtures than for pure substance. A modified correlation was developed based on the previous research of our group on the pool boiling heat transfer and the database obtained from this study. The comparison of the experimental heat transfer coefficient with the predicted value using the present correlation shows that the total mean deviation is 15.97% for R170/R290 mixtures.
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Experimental study on saturated flow boiling heat transfer of R170/R290 mixtures in a Horizontal Tube
International Journal of Refrigeration, 2010Co-Authors: Xin Zou, Maoqiong Gong, Gaofei Chen, Zhaohu Sun, Yan ZhangAbstract:Abstract Saturated flow boiling heat transfer coefficients in a Horizontal Tube of the binary mixtures of R170/R290 were measured. The experiments were performed at three different mixture compositions and various saturation pressures from 0.35 to 0.57 MPa. The results were obtained over the mass fluxes ranging from 63.6 to 102.5 kg m−2 s−1 and heat fluxes ranging from 13.1 to 65.5 kW m−2. The influences of quality, saturation pressure, heat flux and mass flux on the heat transfer characteristic were examined and discussed. The flow pattern of mixture was shown and the transitions of flow pattern occur at higher mass flux and quality for mixtures than for pure substance. A modified correlation was developed based on the previous research of our group on the pool boiling heat transfer and the database obtained from this study. The comparison of the experimental heat transfer coefficient with the predicted value using the present correlation shows that the total mean deviation is 15.97% for R170/R290 mixtures.
Xin Zou - One of the best experts on this subject based on the ideXlab platform.
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experimental investigation on flow condensation heat transfer and pressure drop of r170 in a Horizontal Tube
International Journal of Refrigeration-revue Internationale Du Froid, 2016Co-Authors: Xiaoru Zhuang, Xin Zou, Maoqiong Gong, Gaofei ChenAbstract:Abstract Condensation heat transfer and pressure drop of R170 were studied experimentally in a Horizontal Tube with inner diameter of 4 mm. The tests were conducted at saturation pressures from 1 MPa to 2.5 MPa, mass fluxes from 100 kg (m2∙s)−1 to 250 kg (m2∙s)−1 and average heat fluxes from 55.3 kW m−2 to 96.3 kW m−2 over the entire vapor quality range. The effects of vapor quality, mass flux and saturation pressure on condensation heat transfer and pressure drop were examined and analyzed. The experimental data were compared with various well-known correlations of condensation heat transfer coefficient and pressure drop. The comparison results showed that Koyama et al. correlation agreed with the experimental heat transfer coefficient with a mean absolute relative deviation less than 25%, and the Yan and Lin correlation can accurately predict the experimental pressure drop with a mean absolute relative deviation less than 18%.
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experimental study on saturated flow boiling heat transfer of r170 r290 mixtures in a Horizontal Tube
International Journal of Refrigeration-revue Internationale Du Froid, 2010Co-Authors: Xin Zou, Maoqiong Gong, Gaofei Chen, Zhaohu Sun, Yan ZhangAbstract:Abstract Saturated flow boiling heat transfer coefficients in a Horizontal Tube of the binary mixtures of R170/R290 were measured. The experiments were performed at three different mixture compositions and various saturation pressures from 0.35 to 0.57 MPa. The results were obtained over the mass fluxes ranging from 63.6 to 102.5 kg m−2 s−1 and heat fluxes ranging from 13.1 to 65.5 kW m−2. The influences of quality, saturation pressure, heat flux and mass flux on the heat transfer characteristic were examined and discussed. The flow pattern of mixture was shown and the transitions of flow pattern occur at higher mass flux and quality for mixtures than for pure substance. A modified correlation was developed based on the previous research of our group on the pool boiling heat transfer and the database obtained from this study. The comparison of the experimental heat transfer coefficient with the predicted value using the present correlation shows that the total mean deviation is 15.97% for R170/R290 mixtures.
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Experimental study on saturated flow boiling heat transfer of R170/R290 mixtures in a Horizontal Tube
International Journal of Refrigeration, 2010Co-Authors: Xin Zou, Maoqiong Gong, Gaofei Chen, Zhaohu Sun, Yan ZhangAbstract:Abstract Saturated flow boiling heat transfer coefficients in a Horizontal Tube of the binary mixtures of R170/R290 were measured. The experiments were performed at three different mixture compositions and various saturation pressures from 0.35 to 0.57 MPa. The results were obtained over the mass fluxes ranging from 63.6 to 102.5 kg m−2 s−1 and heat fluxes ranging from 13.1 to 65.5 kW m−2. The influences of quality, saturation pressure, heat flux and mass flux on the heat transfer characteristic were examined and discussed. The flow pattern of mixture was shown and the transitions of flow pattern occur at higher mass flux and quality for mixtures than for pure substance. A modified correlation was developed based on the previous research of our group on the pool boiling heat transfer and the database obtained from this study. The comparison of the experimental heat transfer coefficient with the predicted value using the present correlation shows that the total mean deviation is 15.97% for R170/R290 mixtures.
Shengqiang Shen - One of the best experts on this subject based on the ideXlab platform.
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3d numerical study of the liquid film distribution on the surface of a Horizontal Tube falling film evaporator
International Journal of Heat and Mass Transfer, 2018Co-Authors: Xiaocui Zhang, Shenglin Quan, Shengqiang ShenAbstract:Abstract In this paper, the volume-of-fluid (VOF) model is adopted to simulate the distribution and flow of a liquid film on the outer surface of the Horizontal Tube of a falling-film evaporator. The plain Tube diameter and the spray distance are 25.4 and 22 mm respectively. The temporal variation characteristics of inline jet flow, the adjacent liquid column, and the steady-state film thickness distribution over the Horizontal Tubes are analyzed. To better compare with the experimental results, two kinds of numerical simulation medium, water and ethylene glycol, are chosen. The results of the 3-D numerical simulations and experiment are in good agreement. The results show that the jet flow can be divided into inline jet flow and staggered jet flow. Furthermore, a trough forms between the adjacent liquid columns under inline jet flow, whereas a crest forms between the adjacent liquid columns under staggered jet flow. In addition, the liquid viscosity is a crucial factor affecting the spreading of the liquid film. The appearance of the crest between adjacent liquid columns results in staggered jet flow.
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Experimental Studies on Heat Transfer Coefficients of Horizontal Tube Falling Film Evaporation With Seawater
Journal of Heat Transfer, 2016Co-Authors: Shengqiang Shen, Xue Chen, Changkun JiangAbstract:The overall heat transfer process in a Horizontal Tube falling film evaporator is mainly influenced by the falling film evaporation outside Horizontal Tube due to the average heat transfer coefficient which is about 50% of that of the condensation inside Tube. A series of experimental studies were conducted to investigate the heat transfer coefficients of the falling film evaporation outside the Horizontal Tube with parameters such as the spray density, the evaporation temperature, the salinity, and the Tube spacing. Experiments were conducted by using Al-brass Tubes with 19 mm outer diameter and 1600 mm length. The Horizontal Tubes are arranged vertically in the evaporator. The test Tube is heated by an internal electric heater with uniform heat flux. Temperatures of the test Tube surface and saturated vapor measured by thermocouples are used to calculate the heat transfer coefficients. The seawater with salinity of 1.5%, 3.0%, and 4.5% was used as experimental fluid. The spray density varied between 0.017 and 0.087 kg/(m s), and the evaporation temperature was controlled in the range of 50–70 °C. Results show that the average heat transfer coefficients of water under different salinities increase obviously with the spray density until a certain point. The average heat transfer coefficients of seawater decrease slightly with the evaporation temperature, decrease with the salinity, increase with the Tube spacing, and are almost independent of the heat flux. In addition, the comparisons with 25.4 mm outer diameter Tube and the circumferential distribution of local heat transfer coefficient are presented in this study.
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parametric distributions of a Horizontal Tube falling film evaporator for desalination
Desalination and Water Treatment, 2016Co-Authors: Luyuan Gong, Shengqiang Shen, Xingsen MuAbstract:AbstractThree independent experiments which correspond to the characteristic study on the performance of the Horizontal-Tube falling film evaporators were carried out, and each came out with a validated model for its performance prediction. A comprehensive distributed parameter model was developed based on the above three models to simulate a large Tube bundle consisting of 160 rows and 80 columns aluminum-brass Tubes in a Horizontal-Tube falling film evaporator. The simulation was conducted with the superficial evaporation temperature on the shell side of 60°C, the superficial overall temperature difference of 3.0°C, the inlet brine salinity of 30 g/kg, the inlet brine spray density of 0.06 kg/m s, and the maximum steam inlet velocity of 40 m/s. The non-uniform distributions of several thermal parameters are presented and discussed.
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measurement on falling film thickness distribution around Horizontal Tube with laser induced fluorescence technology
International Journal of Heat and Mass Transfer, 2015Co-Authors: Xue Chen, Shengqiang Shen, Yaoxuan Wang, Juexian Chen, Jieshan ZhangAbstract:Abstract The laser-induced fluorescence technology is used to measure the Horizontal Tube falling film thickness of pure water and natural seawater with 2.66% salinity. This experiment focuses on the film thickness distribution characteristics outside 19 mm and 25.4 mm outside diameter Al-brass Tubes in column flow with the Tube spacing ranging from 20 mm to 40 mm and the Reynolds number varying from 184 to 368. The fluorescent in liquid is induced by the laser. And the images of gas–liquid interface are captured by the digital camera. The quantitative descriptions of the liquid film thickness around the Horizontal Tube are obtained by the image processing technology. The results show that the film thickness increases with Reynolds number and decreases with Tube spacing. In the axial direction, the thickness of the film increases with the distance from the section of liquid column center and maximized at the middle of two adjacent liquid columns. In the circumferential direction, the thickness of the film decreases until it reaches the minimal value near φ = 90° and then increases. The comparison of film thickness between water and seawater is also presented.
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three dimensional heat transfer coefficient distributions in a large Horizontal Tube falling film evaporator
Desalination, 2015Co-Authors: Luyuan Gong, Xingsen Mu, Shengqiang Shen, Xue ChenAbstract:Abstract The distributions of the heat transfer coefficient in a large Horizontal-Tube falling film evaporator under different operating conditions were investigated with numerical simulation in this paper based on the distributed parameter model (DPM). The heat transfer coefficient distributions along the Tube row direction, Tube length direction, and Tube column direction were analyzed with the brine inlet spray density ranging from 0.05 kg/m s to 0.09 kg/m s and the brine inlet salinity from 30 g/kg to 50 g/kg. Results show that the heat transfer coefficient has higher values for the evaporating zone than the preheating zone. With the operating conditions included in this paper, the change of brine inlet salinity leads to a wider variation range of heat transfer coefficient along the Tube length direction for the evaporating zone than the change of brine inlet spray density. The change of brine inlet spray density leads to a wider variation range of heat transfer coefficient along the Tube row direction for the first Tube pass and along the Tube length direction for the preheating zone than the change of brine inlet salinity.