The Experts below are selected from a list of 1560 Experts worldwide ranked by ideXlab platform
Jeremiah K. Kiplagat - One of the best experts on this subject based on the ideXlab platform.
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study on a silica gel water adsorption chiller integrated with a closed Wet Cooling Tower
International Journal of Thermal Sciences, 2010Co-Authors: Congying Chen, R Z Wang, Jeremiah K. KiplagatAbstract:Abstract A silica gel–water adsorption chiller integrated with a closed Wet Cooling Tower is proposed. This adsorption chiller consists of two vacuum chambers, each with one adsorber, one condenser and one evaporator. Vacuum valves were not adopted in this chiller in order to enhance the reliability. A novel heat recovery process was carried out after a mass recovery-like process to improve the coefficient of performance (COP). Integration of the closed Wet Cooling Tower into the chiller could ensure the cleanliness of Cooling water circulating in the chiller and also promote the convenient setup of the chiller. A transient one-dimensional mathematical model was adopted to study this adsorption chiller. The simulated results showed that the Cooling power and COP were 10.76 kW and 0.51 respectively when the hot water inlet temperature, the chilled water inlet temperature, the air inlet Wet bulb temperature and dry bulb temperature were 85, 15, 28 and 30 °C respectively.
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Study on a silica gel–water adsorption chiller integrated with a closed Wet Cooling Tower
International Journal of Thermal Sciences, 2010Co-Authors: Congying Chen, Ruzhu Wang, Jeremiah K. KiplagatAbstract:Abstract A silica gel–water adsorption chiller integrated with a closed Wet Cooling Tower is proposed. This adsorption chiller consists of two vacuum chambers, each with one adsorber, one condenser and one evaporator. Vacuum valves were not adopted in this chiller in order to enhance the reliability. A novel heat recovery process was carried out after a mass recovery-like process to improve the coefficient of performance (COP). Integration of the closed Wet Cooling Tower into the chiller could ensure the cleanliness of Cooling water circulating in the chiller and also promote the convenient setup of the chiller. A transient one-dimensional mathematical model was adopted to study this adsorption chiller. The simulated results showed that the Cooling power and COP were 10.76 kW and 0.51 respectively when the hot water inlet temperature, the chilled water inlet temperature, the air inlet Wet bulb temperature and dry bulb temperature were 85, 15, 28 and 30 °C respectively.
Fengzhong Sun - One of the best experts on this subject based on the ideXlab platform.
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field test study on water droplet diameter distribution in the rain zone of a natural draft Wet Cooling Tower
Applied Thermal Engineering, 2019Co-Authors: Xuehong Chen, Fengzhong Sun, Dongqiang LyuAbstract:Abstract A field test study was conducted on a natural draft Wet Cooling Tower to quantitatively investigate the water droplet diameter distribution in the rain zone for the first time. A test rig with alterable test positions was designed and constructed. The test time for each set of data is 300 s. The test data are presented in the form of a number ratio (R) with water droplet diameter (d). The results manifest that d is scattered between 0.312 mm and 15 mm, regardless of the crosswind velocity. Under low crosswind speed conditions, R has nearly an identical distribution pattern along the circumferential and radial directions, which are relatively large at d = 0.812 mm and 5.5 mm, respectively. As the droplets move from the position of c1r1h1 to c1r1h3, the R at d > 3.75 mm increases significantly, and the difference in R at d = 0.812 mm and d = 5.5 mm increases from 0.7% to 4.1%, respectively. When the crosswind speed is relatively high, the R is basically consistent at different height positions and shows a difference on the windward side, leading to a noticeable increase in R at d
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thermal performance analysis for high level water collecting Wet Cooling Tower under crosswind conditions
Applied Thermal Engineering, 2018Co-Authors: Ming Gao, Jian Zou, Fengzhong SunAbstract:Abstract Field test was conducted on a high level water collecting Wet Cooling Tower (HWCT) of a 1000 MW unit to investigate thermal performance under crosswind conditions. Firstly, the air temperature distribution above drift eliminators was analyzed, and then the changing rules of water temperature drop Δ T and Merkel number N were researched in this study. The results demonstrated that with the rising of crosswind velocity, crosswind appears an increasingly serious adverse effect on the thermal performance and uniformity of air temperature distribution inside Tower. In this paper, χ r stands for the radius radio which can indicate the influencing degree of crosswind, and χ r is approximately 0.78 when the velocity is less than 2.11 m/s, but around 0.60 at 3.74 m/s. Additionally, the intersection angle θ between cross walls and crosswind direction is introduced to analyze the effect of crosswind direction. The testing results discovered that at the same crosswind velocity, the uniformity of air temperature distribution and thermal performance under θ1 = 5° condition are more superior to those under θ2 = 35° condition. When the crosswind velocity reaches to 3.74 m/s, under θ1 = 5° condition, compared with that of 0.28 m/s, Δ T and N reduce by 12.61% and 12.54%, respectively, however, under θ2 = 35° condition, their reductions reach to 15.34% and 13.58%, respectively. It can be obtained that the thermal performance of HWCTs is relatively more outstanding under the smaller θ and/or the lower crosswind velocity.
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thermal performance for Wet Cooling Tower with different layout patterns of fillings under typical crosswind conditions
Energies, 2017Co-Authors: Ming Gao, Yue-tao Shi, Chang Guo, Fengzhong SunAbstract:A thermal-state model experimental study was performed in lab to investigate the thermal performance of a Wet Cooling Tower with different kinds of filling layout patterns under windless and 0.4 m/s crosswind conditions. In this paper, the contrast analysis was focused on comparing a uniform layout pattern and one kind of optimal non-uniform layout pattern when the environmental crosswind speed is 0 m/s and 0.4 m/s. The experimental results proved that under windless conditions, the heat transfer coefficient and total heat rejection of circulating water for the optimal non-uniform layout pattern can enhance by approximately 40% and 28%, respectively, compared with the uniform layout pattern. It was also discovered that the optimal non-uniform pattern can dramatically relieve the influence of crosswind on the thermal performance of the Tower when the crosswind speed is equal to 0.4 m/s. For the uniform layout pattern, the heat transfer coefficient under 0.4 m/s crosswind conditions decreased by 9.5% compared with the windless conditions, while that value lowered only by 2.0% for the optimal non-uniform layout pattern. It has been demonstrated that the optimal non-uniform layout pattern has the better thermal performance under 0.4 m/s crosswind condition.
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impact mechanism of different fill layout patterns on the Cooling performance of the Wet Cooling Tower with water collecting devices
Applied Thermal Engineering, 2017Co-Authors: Dongqiang Lyu, Fengzhong Sun, Yuanbin ZhaoAbstract:This paper deals with the impact mechanism of different fill layout patterns on the Cooling performance of the Wet Cooling Tower with water collecting devices (WCTWCD). A 3D numerical model for the WCTWCD is established and validated. The non-uniform layout fill for the WCTWCD is firstly proposed and analyzed. The differences of the performance parameters caused by the different fill layout patterns are studied. Studies in the paper indicate that the uniform layout fill is not the best layout pattern for the WCTWCD. The non-uniform layout fill can enhance the Tower Cooling performance in both windless and crosswind conditions. To evaluate the ventilation uniformity inside the Tower the circumferential coefficient and the radial coefficient are proposed by the author. The air flow field in the Tower with non-uniform layout fill is more stable and uniform. The coupling of the air flow field and the fill consumption in the Tower with non-uniform layout fill is more reasonable. At last the comparison of the non-uniform layout fill between the conventional Wet Cooling Tower (CWCT) and the WCTWCD is presented.
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experimental study regarding the evolution of temperature profiles inside Wet Cooling Tower under crosswind conditions
International Journal of Thermal Sciences, 2014Co-Authors: Ming Gao, Fengzhong Sun, Ali TuranAbstract:Based on similarity theory, this research details a thermal-state model experiment, concerning the evolution of the air/water temperature profiles inside a Natural Draft Wet Cooling Tower (NDWCT) under windless and crosswind conditions. Prior studies have shown that the air/water temperature distribution is fairly uniform and stable under windless (stagnant) conditions, but the uniformity is destroyed in the presence of windy conditions, and the air/water temperature of different points displays a large variation subject to the same crosswind velocity. Generally speaking, the highest air/water temperature values inside the whole Tower lie on the windward and leeward direction, but the highest air temperature at the Tower outlet appears near the leeward side zone, rather than exactly on the leeward side. Based on this research, the air/water temperature profiles regarding measurement of values can be obtained accurately under windless and crosswind conditions, a fact that can help confirm the specific location of vortex on the windward and leeward side. All of above findings can provide an important theoretical foundation concerning further research, specifically for energy-saving aspects NDWCTs.
Ming Gao - One of the best experts on this subject based on the ideXlab platform.
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an exploratory research on performance improvement of super large natural draft Wet Cooling Tower based on the reconstructed dry Wet hybrid rain zone part 2 crosswind effects
International Journal of Heat and Mass Transfer, 2020Co-Authors: Zhengqing Zhang, Ming Gao, Mingyong Wang, Yang Liu, Yue-tao ShiAbstract:Abstract To enhance the performance of the super-large natural draft Wet Cooling Towers (S-NDWCTs), and finally to achieve the goal of energy-saving in thermal systems, the dry-Wet hybrid rain zone was proposed in our previous paper. However, the previous work failed to discuss the effects of crosswind which are extremely significant for the research for S-NDWCTs. Therefore, the thermal and aerodynamic performances of the Cooling Tower are investigated for variation crosswind speeds (0 m/s ~ 16 m/s) and crosswind angles (0° ~ 45°) by numerical method. The results show that the airflow and circulating water temperature distributions in the dry-Wet Tower are more uniform than those in the usual Tower within the range of studied crosswind velocities; The water temperature drop raises by about 0.40°C on average within the studied crosswind speed range; For the dry-Wet rain zone Tower, while the environment wind speed raises from 2 to 4 m/s, the water temperature drop decreases by 0.63°C, the ventilation rate decreases by 9.5%, the Merkel number decreases by 0.17; The influences of changing crosswind angle on the performance of Wet Cooling Tower are not obvious.
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thermal performance analysis for high level water collecting Wet Cooling Tower under crosswind conditions
Applied Thermal Engineering, 2018Co-Authors: Ming Gao, Jian Zou, Fengzhong SunAbstract:Abstract Field test was conducted on a high level water collecting Wet Cooling Tower (HWCT) of a 1000 MW unit to investigate thermal performance under crosswind conditions. Firstly, the air temperature distribution above drift eliminators was analyzed, and then the changing rules of water temperature drop Δ T and Merkel number N were researched in this study. The results demonstrated that with the rising of crosswind velocity, crosswind appears an increasingly serious adverse effect on the thermal performance and uniformity of air temperature distribution inside Tower. In this paper, χ r stands for the radius radio which can indicate the influencing degree of crosswind, and χ r is approximately 0.78 when the velocity is less than 2.11 m/s, but around 0.60 at 3.74 m/s. Additionally, the intersection angle θ between cross walls and crosswind direction is introduced to analyze the effect of crosswind direction. The testing results discovered that at the same crosswind velocity, the uniformity of air temperature distribution and thermal performance under θ1 = 5° condition are more superior to those under θ2 = 35° condition. When the crosswind velocity reaches to 3.74 m/s, under θ1 = 5° condition, compared with that of 0.28 m/s, Δ T and N reduce by 12.61% and 12.54%, respectively, however, under θ2 = 35° condition, their reductions reach to 15.34% and 13.58%, respectively. It can be obtained that the thermal performance of HWCTs is relatively more outstanding under the smaller θ and/or the lower crosswind velocity.
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thermal performance for Wet Cooling Tower with different layout patterns of fillings under typical crosswind conditions
Energies, 2017Co-Authors: Ming Gao, Yue-tao Shi, Chang Guo, Fengzhong SunAbstract:A thermal-state model experimental study was performed in lab to investigate the thermal performance of a Wet Cooling Tower with different kinds of filling layout patterns under windless and 0.4 m/s crosswind conditions. In this paper, the contrast analysis was focused on comparing a uniform layout pattern and one kind of optimal non-uniform layout pattern when the environmental crosswind speed is 0 m/s and 0.4 m/s. The experimental results proved that under windless conditions, the heat transfer coefficient and total heat rejection of circulating water for the optimal non-uniform layout pattern can enhance by approximately 40% and 28%, respectively, compared with the uniform layout pattern. It was also discovered that the optimal non-uniform pattern can dramatically relieve the influence of crosswind on the thermal performance of the Tower when the crosswind speed is equal to 0.4 m/s. For the uniform layout pattern, the heat transfer coefficient under 0.4 m/s crosswind conditions decreased by 9.5% compared with the windless conditions, while that value lowered only by 2.0% for the optimal non-uniform layout pattern. It has been demonstrated that the optimal non-uniform layout pattern has the better thermal performance under 0.4 m/s crosswind condition.
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experimental study regarding the evolution of temperature profiles inside Wet Cooling Tower under crosswind conditions
International Journal of Thermal Sciences, 2014Co-Authors: Ming Gao, Fengzhong Sun, Ali TuranAbstract:Based on similarity theory, this research details a thermal-state model experiment, concerning the evolution of the air/water temperature profiles inside a Natural Draft Wet Cooling Tower (NDWCT) under windless and crosswind conditions. Prior studies have shown that the air/water temperature distribution is fairly uniform and stable under windless (stagnant) conditions, but the uniformity is destroyed in the presence of windy conditions, and the air/water temperature of different points displays a large variation subject to the same crosswind velocity. Generally speaking, the highest air/water temperature values inside the whole Tower lie on the windward and leeward direction, but the highest air temperature at the Tower outlet appears near the leeward side zone, rather than exactly on the leeward side. Based on this research, the air/water temperature profiles regarding measurement of values can be obtained accurately under windless and crosswind conditions, a fact that can help confirm the specific location of vortex on the windward and leeward side. All of above findings can provide an important theoretical foundation concerning further research, specifically for energy-saving aspects NDWCTs.
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Experimental research on circumferential inflow air and vortex distribution for Wet Cooling Tower under crosswind conditions
Applied Thermal Engineering, 2014Co-Authors: Ming Gao, Fengzhong Sun, Ni-ni Wang, Yuanbin ZhaoAbstract:Abstract Based on similarity theory, this research conducts a thermal-state model experiment, studying the change of circumferential inflow air on the bottom of Wet Cooling Tower and the distribution of vortex inside Tower under environmental crosswind conditions. The study on the circumferential inflow air reveals that the axisymmetric distribution of circumferential inflow air is affected by crosswind, and this phenomenon is very obvious when crosswind velocity is more than 0.2 m/s. At the velocity of 0.4 m/s, the circumferential inflow air velocity in windward side is about 1.875 times that of windless conditions, but the circumferential inflow air velocity in leeward side is about 0.3 times that of windless conditions. Visualization research of vortex distribution reveals that as the crosswind velocity increases, the vortex in windward side enlarges and the vortex in leeward side becomes larger at the beginning, but then gradually disappears; the vortex in leeward side reaches maximum when crosswind velocity is 0.4 m/s. The unsymmetrical circumferential inflow air and vortex under crosswind conditions seriously affect the whole airflowrate of Wet Cooling Tower, and deteriorate the heat and mass transfer performance.
Congying Chen - One of the best experts on this subject based on the ideXlab platform.
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Numerical simulation of a closed Wet Cooling Tower with novel design
International Journal of Heat and Mass Transfer, 2011Co-Authors: Z.z. Xia, Congying Chen, Ruzhu WangAbstract:Abstract A closed Wet Cooling Tower with novel design was proposed and numerically investigated. The studied Cooling Tower consists of two main parts: one heat and mass transfer unit (HMTU) and one heat transfer unit (HTU). In the HMTU, copper tubes are arranged as heat transfer tubes while plastic tubes are collocated to enlarge the mass transfer area between the spray water and the airflow. In the HTU, only copper tubes are adopted as heat transfer tubes. Heat and mass transfer process takes place among the process water, airflow and spray water in the HMTU, while in the HTU only heat transfer between the process water and the spray water is observed. A transient one dimensional distributed-parameter model was adopted to evaluate the Cooling Tower performance under different operating conditions. Determination of heat and mass transfer coefficients, as well as the influence of Lewis number on the Cooling Tower performance, was presented.
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study on a silica gel water adsorption chiller integrated with a closed Wet Cooling Tower
International Journal of Thermal Sciences, 2010Co-Authors: Congying Chen, R Z Wang, Jeremiah K. KiplagatAbstract:Abstract A silica gel–water adsorption chiller integrated with a closed Wet Cooling Tower is proposed. This adsorption chiller consists of two vacuum chambers, each with one adsorber, one condenser and one evaporator. Vacuum valves were not adopted in this chiller in order to enhance the reliability. A novel heat recovery process was carried out after a mass recovery-like process to improve the coefficient of performance (COP). Integration of the closed Wet Cooling Tower into the chiller could ensure the cleanliness of Cooling water circulating in the chiller and also promote the convenient setup of the chiller. A transient one-dimensional mathematical model was adopted to study this adsorption chiller. The simulated results showed that the Cooling power and COP were 10.76 kW and 0.51 respectively when the hot water inlet temperature, the chilled water inlet temperature, the air inlet Wet bulb temperature and dry bulb temperature were 85, 15, 28 and 30 °C respectively.
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Study on a silica gel–water adsorption chiller integrated with a closed Wet Cooling Tower
International Journal of Thermal Sciences, 2010Co-Authors: Congying Chen, Ruzhu Wang, Jeremiah K. KiplagatAbstract:Abstract A silica gel–water adsorption chiller integrated with a closed Wet Cooling Tower is proposed. This adsorption chiller consists of two vacuum chambers, each with one adsorber, one condenser and one evaporator. Vacuum valves were not adopted in this chiller in order to enhance the reliability. A novel heat recovery process was carried out after a mass recovery-like process to improve the coefficient of performance (COP). Integration of the closed Wet Cooling Tower into the chiller could ensure the cleanliness of Cooling water circulating in the chiller and also promote the convenient setup of the chiller. A transient one-dimensional mathematical model was adopted to study this adsorption chiller. The simulated results showed that the Cooling power and COP were 10.76 kW and 0.51 respectively when the hot water inlet temperature, the chilled water inlet temperature, the air inlet Wet bulb temperature and dry bulb temperature were 85, 15, 28 and 30 °C respectively.
Yuanbin Zhao - One of the best experts on this subject based on the ideXlab platform.
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effect of Cooling water salinity on the Cooling performance of natural draft Wet Cooling Tower
International Journal of Heat and Mass Transfer, 2020Co-Authors: Dawei Wan, Shasha Gao, Minghua Liu, Yuanbin ZhaoAbstract:Abstract To clarify the effect of the Cooling water salinity on the Cooling performance of natural draft Wet Cooling Tower (NDWCT) and relevant impact mechanisms, a three-dimensional (3D) numerical model of NDWCT was established with full consideration of the Cooling water salinity, which was validated by comparing with the theoretical code method and the field test data of NDWCT with fresh water. The influences of the Cooling water salinity and ambient crosswind on the key parameters, such as Cooling Tower outlet water temperature, ventilation rate and evaporation of circulating water, were all analyzed. The results show that the Cooling performance of NDWCT with salinity circulating water is weaker than that with fresh water. The ambient crosswind had a great influence on the heat and mass transfer of the Cooling Tower. When the wind speed exceeded 6.6 m/s, the performance of the Cooling Tower is improved, this trend is less affected by salinity. The established 3D numerical model comprehensively considered the influence of salinity and ambient crosswind, the analyzed results are more valuable for practical guidance.
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thermal characteristics of dry Cooling Tower reconstructed from obsolete natural draft Wet Cooling Tower and the relevant thermal system coupling optimization
Applied Thermal Engineering, 2020Co-Authors: Wenjing Ge, Yuanbin Zhao, Wendong Li, Shiwei Song, Tiefeng ChenAbstract:Abstract Natural draft dry Cooling Tower is attractive in recent decades with its superiority of zero water loss. Some old thermal power plants are under high pressure of waste water reducing emission, thus the natural draft Wet Cooling Tower is obsoleted. Reconstructing natural draft Wet Cooling Tower into natural draft dry Cooling Tower is attractive for the saving of capital expenditure. But it has not been researched before, this study aims to fill this gap. Based on an actual reconstruction case, the operation mode of reconstructed dry Cooling system is established and relevant MATLAB programming is realized, which was validated by literature data. The reconstructed system consists of two reconstructed natural draft dry Cooling Towers, a usual natural draft dry Cooling Tower and two 660 MW power units. The Cooling capacity of reconstructed natural draft dry Cooling Tower is lower through thermal characteristic comparison with the usual natural draft dry Cooling Tower. In order to realize the optimal operation, different water distribution schemes are presented and several operation parameters are analyzed. Under the optimized reconstruction design, the annual water saving and annual cost are discussed. The annual water saving is about14.49 million metric tons that is about 8.86 million dollars and the minimum annual cost is about 181.47 million dollars, which brings great economic and environmental benefits.
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impact mechanism of different fill layout patterns on the Cooling performance of the Wet Cooling Tower with water collecting devices
Applied Thermal Engineering, 2017Co-Authors: Dongqiang Lyu, Fengzhong Sun, Yuanbin ZhaoAbstract:This paper deals with the impact mechanism of different fill layout patterns on the Cooling performance of the Wet Cooling Tower with water collecting devices (WCTWCD). A 3D numerical model for the WCTWCD is established and validated. The non-uniform layout fill for the WCTWCD is firstly proposed and analyzed. The differences of the performance parameters caused by the different fill layout patterns are studied. Studies in the paper indicate that the uniform layout fill is not the best layout pattern for the WCTWCD. The non-uniform layout fill can enhance the Tower Cooling performance in both windless and crosswind conditions. To evaluate the ventilation uniformity inside the Tower the circumferential coefficient and the radial coefficient are proposed by the author. The air flow field in the Tower with non-uniform layout fill is more stable and uniform. The coupling of the air flow field and the fill consumption in the Tower with non-uniform layout fill is more reasonable. At last the comparison of the non-uniform layout fill between the conventional Wet Cooling Tower (CWCT) and the WCTWCD is presented.
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Experimental research on circumferential inflow air and vortex distribution for Wet Cooling Tower under crosswind conditions
Applied Thermal Engineering, 2014Co-Authors: Ming Gao, Fengzhong Sun, Ni-ni Wang, Yuanbin ZhaoAbstract:Abstract Based on similarity theory, this research conducts a thermal-state model experiment, studying the change of circumferential inflow air on the bottom of Wet Cooling Tower and the distribution of vortex inside Tower under environmental crosswind conditions. The study on the circumferential inflow air reveals that the axisymmetric distribution of circumferential inflow air is affected by crosswind, and this phenomenon is very obvious when crosswind velocity is more than 0.2 m/s. At the velocity of 0.4 m/s, the circumferential inflow air velocity in windward side is about 1.875 times that of windless conditions, but the circumferential inflow air velocity in leeward side is about 0.3 times that of windless conditions. Visualization research of vortex distribution reveals that as the crosswind velocity increases, the vortex in windward side enlarges and the vortex in leeward side becomes larger at the beginning, but then gradually disappears; the vortex in leeward side reaches maximum when crosswind velocity is 0.4 m/s. The unsymmetrical circumferential inflow air and vortex under crosswind conditions seriously affect the whole airflowrate of Wet Cooling Tower, and deteriorate the heat and mass transfer performance.
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artificial neural network model research on effects of cross wind to performance parameters of Wet Cooling Tower based on level froude number
Applied Thermal Engineering, 2013Co-Authors: Ming Gao, Yuanbin Zhao, Ni-ni Wang, Yue-tao Shi, Fengzhong SunAbstract:Abstract Based on level Froude number ( Fr l ), an artificial neural network (ANN) model is set up to predict performance parameters of Wet Cooling Tower under cross-wind conditions in this paper, enough data are gathered by a thermal state model experiment to finish ANN training and prediction. Then three-layer back propagation network model which has one hidden layer is developed, and the node number in input layer, hidden layer and output layer are 4, 8 and 6, respectively. This model adopts the improved BP algorithm, that is, the gradient descent method with momentum, and the input parameters are level Froude number, water spraying density, inlet water temperature and relative humidity of inlet air, the output parameters are air gravity wind velocity of inlet Tower, temperature difference, Cooling efficiency, heat transfer coefficient, mass transfer coefficient and evaporative loss proportion. This BP model demonstrated a good statistical performance with the MRE and R in the range of 0.48%–3.92% and 0.992–0.999, and the RMSE values for the ANN training and predictions were very low relative to the range of the experiments. Thus, the developed BP model can be used to predict successfully the thermal performance of Wet Cooling Tower under cross-wind conditions.
