The Experts below are selected from a list of 10197 Experts worldwide ranked by ideXlab platform
Guoliang Ding - One of the best experts on this subject based on the ideXlab platform.
-
Effect of Salt Spray Corrosion on Air-Side Performance of Finned-Tube Heat Exchanger with Hydrophilic Coating Under Dehumidifying Conditions
Hvac&r Research, 2010Co-Authors: Guoliang Ding, Yifeng GaoAbstract:In this study, the effect of salt spray corrosion on the air-side performance of finned-tube heat exchangers with Hydrophilic Coating under dehumidifying conditions was experimentally investigated. Artificial accelerated method of salt spray corrosion on the Hydrophilic coated heat exchangers was used for simulating the corrosion process of the actual heat exchangers. The experimental results show that the contact angles of Hydrophilic coated aluminum fins increase with the increase of salt spray corrosion hours, which results in the degradation of Hydrophilicity of fins; the heat transfer is enhanced at lower inlet air velocity and degraded at high inlet air velocity for the pitting corroded heat exchanger with Hydrophilic Coating; compared with the uncorroded finned-tube heat exchanger with Hydrophilic Coating at the inlet air velocity ranging from 0.5 to 2.0 m/s (5905.5 to 23622.0 ft/h), the effects of salt spray corrosion on the air-side heat transfer coefficient and on the air-side pressure drop are ...
-
Airside characteristics of heat, mass transfer and pressure drop for heat exchangers of tube-in Hydrophilic Coating wavy fin under dehumidifying conditions
International Journal of Heat and Mass Transfer, 2009Co-Authors: Guoliang Ding, Yuanming Zhang, Kaijian WangAbstract:Abstract The airside heat, mass and momentum transfer characteristics of seven wavy fin-and-tube heat exchangers with Hydrophilic Coating under dehumidifying conditions were experimented. The test inlet air dry bulb temperatures were 20, 27 and 35 oC, the inlet relative humidity were 50%, 60%, 70% and 80%, and the air velocity were 0.5, 1.0, 2.0, 3.0 and 4.0 m s−1. The test results indicate that both the Colburn jm factor and the Colburn jh factor decrease with the increase of fin pitch, and this phenomenon becomes more and more pronounced as Reynolds number decreases. The friction factor is very sensitive to the change of fin pitch, and the friction factor shows a cross-over phenomenon as fin pitch changes. The Colburn jh factor decreases and the Colburn jm factor increases when the number of tube rows increases, while the friction performance is insensitive to the change of the number of tube rows. The effects of inlet relative humidity on the heat transfer and friction performance can be omitted, but the Colburn jm factor decreases with the increase of the inlet relative humidity. The predictive ability of the available state-of-the-art heat transfer and pressure drop correlations was evaluated with the experiment data of the present study. The new heat, mass and momentum transfer correlations were proposed to describe the present test results according to the multiple linear regression technique. The mean deviations of the proposed jh, jm and f correlations are 6.3%, 8.9% and 7.9%, respectively. Comparing to published data reduction method, the process line on psychrometric chart of fin-and-tube heat exchanger for partially wet conditions and more accurate overall heat transfer coefficient equation are put forward in this paper.
-
effects of biofouling on air side heat transfer and pressure drop for finned tube heat exchangers
International Journal of Refrigeration-revue Internationale Du Froid, 2009Co-Authors: Guoliang Ding, Yifeng GaoAbstract:Experimental investigations on the effects of biofouling on air-side heat transfer and pressure drop for three biofouled finned tube heat exchangers and one clean finned tube heat exchanger were performed. Artificial accelerated method of microorganism growth on the fin surface was used for simulating the biofouled finned tube heat exchangers. Experimental results indicate that the effects of biofouling on the air-side heat transfer coefficient decreases 7.2% at 2.0 m/s when the biofouled area ratio is 10%, while it decreases 15.9% at 2.0 m/s when the biofouled area ratio is 60%, and biofouling causes a 21.8% ∼ 41.3% increase in pressure drop when the air velocity is between 0.5 and 2.0 m/s. The increase of inlet air velocity is helpful to improve the long-term performance of finned tube heat exchanger. Biofouling makes the Hydrophilic Coating failure, and the condensation water easily converges on the fin surface where biofouling grows.
-
Experimental study of the airside performance for interrupted fin-and-tube heat exchanger with Hydrophilic Coating under dehumidifying conditions
Journal of Shanghai Jiaotong University (science), 2009Co-Authors: Guoliang Ding, Yuanming ZhangAbstract:The airside heat transfer and friction characteristics of seven interrupted fin-and-tube heat exchangers with Hydrophilic Coating under dehumidifying conditions are experimented. The effects of number of tube rows, fin pitch and inlet relative humidity on airside performance are analyzed. The test results show that the influence of fin pitch on the friction characteristic under dehumidifying conditions is similar to that under dry surface, and the friction factors decrease slightly with the increase of number of tube rows. The heat transfer performance decreases as fin pitch and number of tube rows increases. The heat transfer performance and the friction characteristic are independent of inlet relative humidity. Based on the test results, heat transfer and friction correlations in terms of the Colburn j factor and Fanning f factor, are proposed to describe the airside performance of the interrupted fin geometry with Hydrophilic Coating under dehumidifying conditions. The correlation of the Colburn j factor gives a mean deviation of 9.7%, while the correlation of the Fanning f factor shows a mean deviation of 7.3%.
-
airside heat transfer and friction characteristics for enhanced fin and tube heat exchanger with Hydrophilic Coating under wet conditions
International Journal of Refrigeration-revue Internationale Du Froid, 2007Co-Authors: Guoliang Ding, Yuanming Zhang, Kaijia WangAbstract:The airside heat transfer and friction characteristics of 14 enhanced fin-and-tube heat exchangers with Hydrophilic Coating under wet conditions are experimented. The effects of number of tube rows, fin pitch and inlet relative humidity on airside performance are analyzed. The test results show that the influences of the fin pitch and the number of tube rows on the friction characteristic under wet conditions are similar to that under dry surface owing to the existence of the Hydrophilic Coating. The Colburn j factors decrease as the fin pitch and the number of tube rows increase. For wavy fin, the Colburn j factors increase with the increase of the inlet relative humidity, but for interrupted fin, the Colburn j factors are relatively insensitive to the change of the inlet relative humidity. The friction characteristic is independent of the inlet relative humidity. Based on the test results, heat transfer and friction correlations, in terms of the Colburn j factor and Fanning f factor, are proposed to describe the airside performance of the enhanced fin geometry with Hydrophilic Coating under wet conditions. For wavy fin, the correlation of the Colburn j factor gives a mean deviation of 7.6%, while the correlation of Fanning f factor shows a mean deviation of 9.1%. For interrupted fin, the correlation of the Colburn j factor gives a mean deviation of 9.7%, while the correlation of Fanning f factor shows a mean deviation of 7.3%.
Yifeng Gao - One of the best experts on this subject based on the ideXlab platform.
-
Effect of Salt Spray Corrosion on Air-Side Performance of Finned-Tube Heat Exchanger with Hydrophilic Coating Under Dehumidifying Conditions
Hvac&r Research, 2010Co-Authors: Guoliang Ding, Yifeng GaoAbstract:In this study, the effect of salt spray corrosion on the air-side performance of finned-tube heat exchangers with Hydrophilic Coating under dehumidifying conditions was experimentally investigated. Artificial accelerated method of salt spray corrosion on the Hydrophilic coated heat exchangers was used for simulating the corrosion process of the actual heat exchangers. The experimental results show that the contact angles of Hydrophilic coated aluminum fins increase with the increase of salt spray corrosion hours, which results in the degradation of Hydrophilicity of fins; the heat transfer is enhanced at lower inlet air velocity and degraded at high inlet air velocity for the pitting corroded heat exchanger with Hydrophilic Coating; compared with the uncorroded finned-tube heat exchanger with Hydrophilic Coating at the inlet air velocity ranging from 0.5 to 2.0 m/s (5905.5 to 23622.0 ft/h), the effects of salt spray corrosion on the air-side heat transfer coefficient and on the air-side pressure drop are ...
-
effects of biofouling on air side heat transfer and pressure drop for finned tube heat exchangers
International Journal of Refrigeration-revue Internationale Du Froid, 2009Co-Authors: Guoliang Ding, Yifeng GaoAbstract:Experimental investigations on the effects of biofouling on air-side heat transfer and pressure drop for three biofouled finned tube heat exchangers and one clean finned tube heat exchanger were performed. Artificial accelerated method of microorganism growth on the fin surface was used for simulating the biofouled finned tube heat exchangers. Experimental results indicate that the effects of biofouling on the air-side heat transfer coefficient decreases 7.2% at 2.0 m/s when the biofouled area ratio is 10%, while it decreases 15.9% at 2.0 m/s when the biofouled area ratio is 60%, and biofouling causes a 21.8% ∼ 41.3% increase in pressure drop when the air velocity is between 0.5 and 2.0 m/s. The increase of inlet air velocity is helpful to improve the long-term performance of finned tube heat exchanger. Biofouling makes the Hydrophilic Coating failure, and the condensation water easily converges on the fin surface where biofouling grows.
Kaijia Wang - One of the best experts on this subject based on the ideXlab platform.
-
airside heat transfer and friction characteristics for enhanced fin and tube heat exchanger with Hydrophilic Coating under wet conditions
International Journal of Refrigeration-revue Internationale Du Froid, 2007Co-Authors: Guoliang Ding, Yuanming Zhang, Kaijia WangAbstract:The airside heat transfer and friction characteristics of 14 enhanced fin-and-tube heat exchangers with Hydrophilic Coating under wet conditions are experimented. The effects of number of tube rows, fin pitch and inlet relative humidity on airside performance are analyzed. The test results show that the influences of the fin pitch and the number of tube rows on the friction characteristic under wet conditions are similar to that under dry surface owing to the existence of the Hydrophilic Coating. The Colburn j factors decrease as the fin pitch and the number of tube rows increase. For wavy fin, the Colburn j factors increase with the increase of the inlet relative humidity, but for interrupted fin, the Colburn j factors are relatively insensitive to the change of the inlet relative humidity. The friction characteristic is independent of the inlet relative humidity. Based on the test results, heat transfer and friction correlations, in terms of the Colburn j factor and Fanning f factor, are proposed to describe the airside performance of the enhanced fin geometry with Hydrophilic Coating under wet conditions. For wavy fin, the correlation of the Colburn j factor gives a mean deviation of 7.6%, while the correlation of Fanning f factor shows a mean deviation of 9.1%. For interrupted fin, the correlation of the Colburn j factor gives a mean deviation of 9.7%, while the correlation of Fanning f factor shows a mean deviation of 7.3%.
Chichuan Wang - One of the best experts on this subject based on the ideXlab platform.
-
A comparison of the airside performance of the fin-and-tube heat exchangers in wet conditions; with and without Hydrophilic Coating
Applied Thermal Engineering, 2002Co-Authors: Chichuan Wang, Wei Song Lee, Wen Jenn Sheu, Yu Juei ChangAbstract:An experimental study was performed on compact fin-and-tube heat exchangers in wet conditions. Airside performance for both Hydrophilic coated and un-coated surface is examined. It is found that the effect of inlet relative humidity on the heat transfer performance is small. For un-coated surfaces, the effect of inlet relative humidity has a pronounced effect on pressure drops. It is likely that this phenomenon is related to the condensate flow pattern along the fin surface. The heat transfer performance for the Hydrophilic Coating surface is lower than the corresponding un-coated surface tested at the same wet condition. Further, the degradation of heat transfer performance may be up to 20% for fin pitches of 1.2 mm. The pressure drops for the Hydrophilic coated surface are also lower than the corresponding un-coated surfaces. A maximum 40% reduction is observed for plain fin geometry. The effect of inlet condition on frictional performance is more pronounced in the enhanced slit geometry.
-
heat and mass transfer for plate fin and tube heat exchangers with and without Hydrophilic Coating
International Journal of Heat and Mass Transfer, 1998Co-Authors: Chichuan Wang, Chang Tsair ChangAbstract:Abstract Heat and mass transfer characteristics of fin-and-tube heat exchangers with and without Hydrophilic Coating were reported in this study. The test exchangers consisted of three different louvre fin patterns and their corresponding plain fin counterpart. For completely dry test conditions, the enhancement level for the enhanced fin pattern decreases with increase of fin pitch. The Gray and Webb correlation considerably under-predicts the present 7.0 and 9.5 mm tube diameter plain fin samples. For dehumidifying test conditions, the effect of Hydrophilic Coating on the sensible heat transfer coefficients is negligible, and there are no detectable changes of the sensible heat transfer coefficients with change of inlet relative humidity. However, the pressure drops for the Hydrophilic coated surfaces are sensitive to the inlet relative humidity.
Purnendu K Dasgupta - One of the best experts on this subject based on the ideXlab platform.
-
low bleed silica based stationary phase for Hydrophilic interaction liquid chromatography
Analytical Chemistry, 2018Co-Authors: Kun Qian, Zhanqiang Yang, Feifang Zhang, Bingcheng Yang, Purnendu K DasguptaAbstract:Bleeding of Hydrophilic interaction liquid chromatographic (HILIC) phases is a major problem. A hydrophobic silica surface exhibits low bleeding but does not behave as a HILIC phase. A Hydrophilic Coating, such as that of poly(vinyl alcohol) (PVA) on a hydrophobic particle should result in a low-bleed Hydrophilic phase. However, a silica particle functionalized in a hydrophobic manner is not wetted by PVA and cannot be coated with it. Coating with PVA becomes possible if one region of the hydrophobic functionality is polar. We describe a low-bleed HILIC stationary phase, PVA-coated benzylthioethyl-silica. The benzyl groups shield the silica from water erosion, while the thiol group provides sufficient local polarity for PVA to wet the material. The new stationary phase demonstrated good chromatographic performance and typical HILIC retention behavior. The measured silica concentration in the effluent was ∼80-fold lower than that from a bare silica column. The new stationary phase exhibited a lower backgro...
