Numerical study on the cooling performance of dry cooling tower with vertical two-pass column radiators under crosswind

Zhao, Yuan; Long, Guoqing; Sun, Fengzhong; Li, Yan; Zhang, Cuijiao

doi:10.1016/j.applthermaleng.2014.10.061

Cited by 85 publications

(65 citation statements)

References 18 publications

(28 reference statements)

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“…This further prevents the air flowing into the tower and allows some hot air to flow out of the cooling tower. Under certain crosswind speeds, the pressure difference between the inlet and outlet of the side section could be very low, reducing air mass flow rate through the side section to almost zero [38,39,57]. For the leeward section of the cooling tower, at low crosswind speed condition, crosswind effect is not significant.…”

Section: Crosswind Effect On the Nddctvmentioning

confidence: 94%

“…For the NDDCTV, the thermal performance is believed to be more susceptible to the crosswind than those with horizontal arranged heat exchanger [38,44,49,57,70,75,76]. For this kind of NDDCT where the vertically oriented heat exchanger panels are distributed around the tower perimeter with direct exposure to crosswind, the mechanism of crosswind effect are totally different.…”

Section: Crosswind Effect On the Nddctvmentioning

confidence: 99%

“…can cause extra air flow though the heat exchangers. According to Yang and Zhao's simulation [38,57], the air mass flow rate in the windward section is the largest and increases continuously with 31 increased crosswind speed. For the side section, the aerodynamic performance is like the flow over a vertical cylinder [36].…”

Section: Crosswind Effect On the Nddctvmentioning

confidence: 99%

“…Because the cooling tower structure is axially symmetric, a number of researchers limited the numerical analysis to half, quarter or 45 o wedges of the cooling tower to reduce the computation cost [37,57]. Both structured and unstructured meshes have been applied in the cooling tower modelling.…”

Section: Cfd Simulationmentioning

confidence: 99%

“…In dry cooling tower simulation, the radiator boundary condition is the most common way to model the heat exchanger [36,37,39,57,[68][69][70][71]. For example, the radiator model in Fluent [72] is defined as a lumped face without thickness and heat transfer process can be presented by the following equation:…”

Section: Cfd Simulationmentioning

confidence: 99%

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Numerical and experimental study of small natural draft dry cooling tower for concentrating solar thermal power plant

Li¹

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The typically arid climates in the likely locations for renewable thermal power plants such as Concentrating Solar Thermal (CST) power plants provide the motivation for dry cooling technology applications. Natural draft dry cooling tower (NDDCT) with low maintenance cost and no parasitic power consumption offers a feasible and cost effective option for such applications. Compared with the conventional coal fired and nuclear power plants, the size of the CST power plant proposed for Australian regional communities is much smaller. However, the existing cooling tower design is optimised for large steam power plants, and is not optimal for these renewable power plants. (2) The performance of the experimental tower was tested at two constant heat loads of 600 kW and 840 kW, respectively, with various ambient temperatures. The 1D numerical model was refined and validated with the experimental data. The thermodynamic model of a 1 MW CST power plant running with sCO2 cycle was developed and integrated with the updated cooling tower model. Significant differences were observed between the steam Rankine and sCO2 cycles in terms of the effect of the ambient temperature on power generation. The differences between steam Rankine and sCO2 Brayton cycle in this context were analysed and discussed.(3) Two potential cooling issues with small NDDCT, the crosswind and the cold inflow, were identified and the detail experimental data were presented. The crosswind effect on small cooling tower is different from the conventional big cooling towers. With the increase of the crosswind speed, the overall cooling performance of the small NDDCT first decreases and then increases. The mixed convection theory and the Richardson Number were proposed to explain this phenomenon. On the other hand, repeated cold inflow events were observed during the tests, which cause a significant decrease of the air temperature inside the cooling tower. The water outlet temperature can be increased up to 3°C as a result of the cold inflow effect. Further analysis of the mechanism shows that the cold air incursion at the top of the cooling tower could decrease the driving force and also form an extra flow resistance for the airflow through the heat exchanger.(4) Based on the working mechanism of the air-cooled heat exchanger and the crosswind effect on NDDCT, this study proposed a new method to increase the cooling performance of NDDCT under crosswind conditions by optimizing the water mass flow rate in the air-cooled heat exchangers. By optimising the water distribution, the water outlet temperature of each heat exchanger is more uniform and the adversely influence of the crosswind can be effectively relieved.The findings in this paper can lay an important foundation for future small cooling tower design and operation.

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Section: Crosswind Effect On the Nddctvmentioning

confidence: 94%