The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
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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field test on ventilation performance for high level water collecting wet cooling tower under Crosswind conditions
Applied Thermal Engineering, 2018Co-Authors: Jian Zou, Guoqing Long, Fengzhong Sun, Ming GaoAbstract:Abstract Field test was performed on the high level water collecting wet cooling towers (HWCTs) of a 1000 MW unit to investigate ventilation performance under Crosswind conditions, the circumferential inflow air distribution rules and ventilation rate were analyzed in this paper. The test results manifest that Crosswind destroys the uniformity of circumferential inflow air, increases the wind velocity in the windward side, and reduces wind velocity in the lateral and leeward side. Moreover, the uniformity coefficient of circumferential inflow air and ventilation rate continuously decrease with the increasing of Crosswind velocity. In this study, θ represents the angle between cross walls and Crosswind direction. When Crosswind velocity reaches to 3.74 m/s, the uniformity coefficient decreases to 0.61 and 0.49 under θ1 = 5° and θ2 = 35°. Compared with 0.28 m/s condition, the ventilation rate reduces by 30.13% under θ1 = 5° and 34.36% under θ2 = 35°. Additionally, at the same Crosswind velocity, the smaller the θ is, the better the ventilation performance becomes. Compared with θ2 = 35°, the uniformity of circumferential inlet air is better and the ventilation rate is larger than that under θ1 = 5° condition.
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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 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.
Fengzhong Sun - One of the best experts on this subject based on the ideXlab platform.
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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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field test on ventilation performance for high level water collecting wet cooling tower under Crosswind conditions
Applied Thermal Engineering, 2018Co-Authors: Jian Zou, Guoqing Long, Fengzhong Sun, Ming GaoAbstract:Abstract Field test was performed on the high level water collecting wet cooling towers (HWCTs) of a 1000 MW unit to investigate ventilation performance under Crosswind conditions, the circumferential inflow air distribution rules and ventilation rate were analyzed in this paper. The test results manifest that Crosswind destroys the uniformity of circumferential inflow air, increases the wind velocity in the windward side, and reduces wind velocity in the lateral and leeward side. Moreover, the uniformity coefficient of circumferential inflow air and ventilation rate continuously decrease with the increasing of Crosswind velocity. In this study, θ represents the angle between cross walls and Crosswind direction. When Crosswind velocity reaches to 3.74 m/s, the uniformity coefficient decreases to 0.61 and 0.49 under θ1 = 5° and θ2 = 35°. Compared with 0.28 m/s condition, the ventilation rate reduces by 30.13% under θ1 = 5° and 34.36% under θ2 = 35°. Additionally, at the same Crosswind velocity, the smaller the θ is, the better the ventilation performance becomes. Compared with θ2 = 35°, the uniformity of circumferential inlet air is better and the ventilation rate is larger than that under θ1 = 5° condition.
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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 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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experimental research of the cross walls effect on the thermal performance of wet cooling towers under Crosswind conditions
Applied Thermal Engineering, 2011Co-Authors: Youliang Chen, Fengzhong Sun, Hongguo Wang, Ming GaoAbstract:This paper describes a hot model test of natural draft wet cooling towers (NDWCTs) to investigate the effect of cross walls on the thermal performance of NDWCTs under Crosswind conditions. The hot model test can simulate the actual operation of a prototype tower by operating a model tower at steady state conditions while varying the temperature and flow rate of the incoming hot water along with the Crosswind velocity. Cross walls of two shapes at different setting angles were installed in the rain zone and tested under various operating conditions. The results show that Crosswinds degrade the NDWCT performance below a critical Crosswind velocity Vcr, but improve the performance above Vcr. Increasing water flow rate and inlet water temperature can raise Vcr. Installing cross walls can improve the NDWCT performance. At low Crosswind velocities, the solid wall leads to better NDWCT performance than the porous wall. However, the opposite effect is obtained at high Crosswind velocities. At all Crosswind velocities, the cross wall at a setting angle of 0° results in higher performance than that at 45°, regardless of cross wall shapes. Moreover, the cross wall at 45° degrades the NDWCT performance under high Crosswind conditions.
Masud Behnia - One of the best experts on this subject based on the ideXlab platform.
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CFD simulation of wet cooling towers
Applied Thermal Engineering, 2006Co-Authors: Rafat Al-waked, Masud BehniaAbstract:Abstract Heat and mass transfer inside a natural draft wet cooling tower (NDWCT) have been investigated numerically under different operating and Crosswind conditions. The three-dimensional CFD model has utilized the standard k – e turbulence model as the turbulence closure. The current simulation has adopted both the Eulerian approach for the air phase and the Lagrangian approach for the water phase. The film nature of the water flow in the fill zone has been approximated by droplets flow with a given velocity. The required heat and mass transfer have been achieved by controlling the droplet velocity. At that specific droplet velocity, effects of the following operating parameters on the thermal performance of the NDWCT have been investigated: droplet diameter, inlet water temperature, number of nozzles, water flow rate and number of tracks per nozzle. As a result, the effect of Crosswind velocity on the thermal performance has been found to be significant. Crosswinds with velocity magnitude higher than 7.5 m/s have enhanced the thermal performance of the NDWCT.
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The performance of natural draft dry cooling towers under Crosswind: CFD study
International Journal of Energy Research, 2004Co-Authors: Rafat Al-waked, Masud BehniaAbstract:The thermal performance of a natural draft dry cooling tower (NDDCT) under a Crosswind has been investigated using a general-purpose CFD code. A three-dimensional study using the standard k-e turbulence model to simulate airflow in and around an NDDCT has been conducted. A parametric study has been carried out to examine the effect of Crosswind velocity profile and air dry-bulb temperature on the thermal performance of an NDDCT. Two approaches have been considered in this study to quantify the Crosswind effect. Firstly, simulations have been conducted at the nominal conditions and Crosswind effect has been represented by thermal effectiveness parameter. Secondly, the ejected heat from the NDDCT has been maintained at a constant value (285 MW) and the Crosswind effect has been represented by the change in the cooling tower approach parameter. After quantifying the effect of the Crosswind on the thermal performance, windbreak walls have been introduced as a means of reducing this effect. The results in this paper show the importance of considering the Crosswind velocity profile. Moreover, the introduction of windbreak walls has indicated an improvement in reducing the thermal performance losses due to the Crosswind.
Zhiqiang Guan - One of the best experts on this subject based on the ideXlab platform.
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A review of the Crosswind effect on the natural draft cooling towers
Applied Thermal Engineering, 2019Co-Authors: Hal Gurgenci, Xurong Wang, Zhiqiang Guan, Lin XiaAbstract:Abstract Crosswind is a significant concern for the design and operation of a natural draft cooling tower. The negative effects of Crosswind on the thermal performance of natural draft cooling towers have been shown in many cases, for a variety of tower types. This paper presents a comprehensive review to synthesize the current research status in this field. At first, three common cooling tower research methods used to quantify the Crosswind effect: full-scale/field measurements, lab-scale tests and CFD modelling, are reviewed and discussed. Then, based on the existing literature, the Crosswind effect and its working mechanism on different types of natural draft cooling towers are summarized and discussed. Finally, the most current findings and solutions to address the Crosswind issue are reported. The main advantages and disadvantages of each solution are presented and discussed. The information collected in this review paper could be a useful guidance for the design and optimization of natural draft cooling tower.
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measurements of Crosswind influence on a natural draft dry cooling tower for a solar thermal power plant
Applied Energy, 2017Co-Authors: Xiaoxiao Li, Zhiqiang Guan, Xurong Wang, Hal Gurgenci, Sam DuniamAbstract:Crosswind is a significant concern for natural draft dry cooling towers. The concern is more serious for shorter towers. Therefore, the Crosswind influence is a significant threat to the use of natural draft dry cooling towers in concentrating solar thermal power plants, which are generally built at sizes smaller than conventional fossil-fired plants and employ relatively shorter towers. While some numerical studies and small lab-scale test reports exist, very few full scale experimental studies have been reported for conventional cooling towers and none for relatively short cooling towers suitable for renewable thermal power plants. To address this gap, a 20-m tall fully instrumented natural draft dry cooling tower was built by the University of Queensland. The tower was designed to serve a future 1-MWe concentrating solar thermal plant on the same site. Its performance was tested under different ambient temperatures and Crosswind speeds. The detailed experimental data of the Crosswind condition, air temperature distribution inside and outside of the cooling tower and the cooling performance are presented. The experimental data demonstrate the substantial yet complex impact of the Crosswind on cooling tower performance. Significant non-uniformities in air and hot water temperature distributions and strong air vortices inside the tower were observed in high Crosswind speeds. Unlike tall cooling towers used in large conventional plants, the cooling tower performance does not monotonously decrease with the increase of the Crosswind speed. In fact, after the tower performance drops to its lowest level at a wind speed around 5 m/s, the trend is reversed and further increases in the Crosswind speed help the tower performance. Analysis shows that this reversal occurs because the tower heat transfer mechanism changes. As Crosswind rises above the critical speed, the airflow inside the cooling tower becomes increasingly controlled by the Crosswind instead of the natural draft.
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performance enhancement for the natural draft dry cooling tower under Crosswind condition by optimizing the water distribution
International Journal of Heat and Mass Transfer, 2017Co-Authors: Xiaoxiao Li, Hal Gurgenci, Zhiqiang GuanAbstract:Crosswind is a big challenge to the cooling performance of natural draft dry cooling towers (NDDCTs) and has attracted a lot of attention in previous research. This study proposed a new method to increase the performance of NDDCT under Crosswind conditions by optimizing the hot water mass flow rate in the air-cooled heat exchangers. The 20 m UQ Gatton NDDCT was selected as a case study to test and validate this method. The cooling performance of this cooling tower under Crosswind condition was evaluated by the 3-D CFD model. The results show that the Crosswind redistributes the air flow and result in a non-uniform heat exchanger performance. By optimizing the hot water mass flow rate among the heat exchanger bundles, the cold fluids and hot fluids of the air-cooled heat exchanger can be better matched. The cooling performance of the NDDCT is increased by 18% when the Crosswind speed is 4 m/s.
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simulation of the uq gatton natural draft dry cooling tower
Applied Thermal Engineering, 2016Co-Authors: Xiaoxiao Li, Yuanshen Lu, Zhiqiang Guan, Hal Gurgenci, Suoying HeAbstract:A natural draft dry cooling tower (NDDCT) is a cost-effective cooling technology which can be utilized in most of the small renewable power plants. While a number of numerical studies have been done on NDDCTs in recent decades, experimental studies on full scale small cooling tower are very few. To fill this gap, Queensland Geothermal Energy Centre of Excellence (QGECE) has built a 20 m NDDCT. In this study, a 1-D analytical and a 3-D CFD models of this cooling tower were developed and the cooling performance was investigated at different ambient temperatures, inlet water temperatures and Crosswind speeds. The results show that NDDCT in such a size is capable for a 2–3 MW CST power plant. The cooling performance of the NDDCT decreases with the increase in the ambient temperature and the decrease in the inlet water temperature. In terms of the Crosswind, the heat rejection ratio decreases with the increase of the Crosswind velocity at low Crosswind speeds. However, when the Crosswind speed becomes large enough, the heat dumped at the bottom of the tower can compensate some losses in cooling capacity caused by Crosswind. The results found in the present study give reference for future tests.
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Performance comparison of the Crosswind effect on different size of natural draft dry cooling towers
2016Co-Authors: Hal Gurgenci, Zhiqiang GuanAbstract:Previous research have identified that the performance of the natural draft dry cooling tower (NDDCT) is seriously influenced by the Crosswind. For different size and different shape of the cooling towers, the Crosswind effects are different. In order to better compare the Crosswind effect on the different size of the cooling tower, this paper developed four different NDDCT models with the horizontal arranged air-cooled heat exchanger. The heights of the towers are 20m, 60m, 100m and 140m with the same aspect ratio and same aircooled heat exchanger. The cooling performance of these four cooling towers under Crosswind condition were evaluated by the 3-D CFD models and the mechanism of the Crosswind effect on the cooling tower was discussed.
Xiaoxiao Li - One of the best experts on this subject based on the ideXlab platform.
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positive impact of a tower inlet cover on natural draft dry cooling towers under Crosswind conditions
Applied Thermal Engineering, 2018Co-Authors: Mengqi Hu, Xiaoxiao Li, Zihao MiAbstract:Abstract This study proposes a tower inlet cover to improve the performance of the small natural draft dry cooling tower (NDDCT) under Crosswind conditions. CFD analyses are performed on a small NDDCT with tower inlet covers of different lengths, and the CFD model is validated against experimental results. The air temperature, air pressure, air flow and heat flux fields are presented, and the thermal performance for each heat exchanger and the NDDCT are obtained using CFD simulations. The CFD simulation results show that the high-pressure zone around the tower side wall, formed by the Crosswind, causes the decrease in air flow through the tower and the deterioration in tower performance with a Crosswind. The tower inlet cover can improve the tower performance in Crosswinds by increasing the air flow of the heat exchangers. Tower inlet covers with lengths of 1.5 m, 3 m and 4.5 m improve the tower heat load by 40–65%, 70–130% and 85–230%, respectively, when the Crosswind increases from 4 m/s to 12 m/s.
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measurements of Crosswind influence on a natural draft dry cooling tower for a solar thermal power plant
Applied Energy, 2017Co-Authors: Xiaoxiao Li, Zhiqiang Guan, Xurong Wang, Hal Gurgenci, Sam DuniamAbstract:Crosswind is a significant concern for natural draft dry cooling towers. The concern is more serious for shorter towers. Therefore, the Crosswind influence is a significant threat to the use of natural draft dry cooling towers in concentrating solar thermal power plants, which are generally built at sizes smaller than conventional fossil-fired plants and employ relatively shorter towers. While some numerical studies and small lab-scale test reports exist, very few full scale experimental studies have been reported for conventional cooling towers and none for relatively short cooling towers suitable for renewable thermal power plants. To address this gap, a 20-m tall fully instrumented natural draft dry cooling tower was built by the University of Queensland. The tower was designed to serve a future 1-MWe concentrating solar thermal plant on the same site. Its performance was tested under different ambient temperatures and Crosswind speeds. The detailed experimental data of the Crosswind condition, air temperature distribution inside and outside of the cooling tower and the cooling performance are presented. The experimental data demonstrate the substantial yet complex impact of the Crosswind on cooling tower performance. Significant non-uniformities in air and hot water temperature distributions and strong air vortices inside the tower were observed in high Crosswind speeds. Unlike tall cooling towers used in large conventional plants, the cooling tower performance does not monotonously decrease with the increase of the Crosswind speed. In fact, after the tower performance drops to its lowest level at a wind speed around 5 m/s, the trend is reversed and further increases in the Crosswind speed help the tower performance. Analysis shows that this reversal occurs because the tower heat transfer mechanism changes. As Crosswind rises above the critical speed, the airflow inside the cooling tower becomes increasingly controlled by the Crosswind instead of the natural draft.
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performance enhancement for the natural draft dry cooling tower under Crosswind condition by optimizing the water distribution
International Journal of Heat and Mass Transfer, 2017Co-Authors: Xiaoxiao Li, Hal Gurgenci, Zhiqiang GuanAbstract:Crosswind is a big challenge to the cooling performance of natural draft dry cooling towers (NDDCTs) and has attracted a lot of attention in previous research. This study proposed a new method to increase the performance of NDDCT under Crosswind conditions by optimizing the hot water mass flow rate in the air-cooled heat exchangers. The 20 m UQ Gatton NDDCT was selected as a case study to test and validate this method. The cooling performance of this cooling tower under Crosswind condition was evaluated by the 3-D CFD model. The results show that the Crosswind redistributes the air flow and result in a non-uniform heat exchanger performance. By optimizing the hot water mass flow rate among the heat exchanger bundles, the cold fluids and hot fluids of the air-cooled heat exchanger can be better matched. The cooling performance of the NDDCT is increased by 18% when the Crosswind speed is 4 m/s.
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simulation of the uq gatton natural draft dry cooling tower
Applied Thermal Engineering, 2016Co-Authors: Xiaoxiao Li, Yuanshen Lu, Zhiqiang Guan, Hal Gurgenci, Suoying HeAbstract:A natural draft dry cooling tower (NDDCT) is a cost-effective cooling technology which can be utilized in most of the small renewable power plants. While a number of numerical studies have been done on NDDCTs in recent decades, experimental studies on full scale small cooling tower are very few. To fill this gap, Queensland Geothermal Energy Centre of Excellence (QGECE) has built a 20 m NDDCT. In this study, a 1-D analytical and a 3-D CFD models of this cooling tower were developed and the cooling performance was investigated at different ambient temperatures, inlet water temperatures and Crosswind speeds. The results show that NDDCT in such a size is capable for a 2–3 MW CST power plant. The cooling performance of the NDDCT decreases with the increase in the ambient temperature and the decrease in the inlet water temperature. In terms of the Crosswind, the heat rejection ratio decreases with the increase of the Crosswind velocity at low Crosswind speeds. However, when the Crosswind speed becomes large enough, the heat dumped at the bottom of the tower can compensate some losses in cooling capacity caused by Crosswind. The results found in the present study give reference for future tests.