Crosswinds effect on the performance of natural draft wet cooling towers

Al-Waked, Rafat

doi:10.1016/j.ijthermalsci.2009.07.012

Cited by 76 publications

(26 citation statements)

References 14 publications

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“…In the spray and rain zones, discrete phase modelling (DPM) is used to simulate the air-water interaction, with the water phase represented as the discrete phase [60][61][62][63][64]. The Eulerian framework is utilized to describe the continuous phase (air), while the Lagrangian trajectory simulations are 20 performed for the discrete phase (water droplets) [65].…”

Section: Cfd Simulationmentioning

confidence: 99%

“…Because of the reduced driving force, the air mass flow rate through the windward part of the cooling tower is decreased and a non-uniform airflow distribution is formed. Since most of the heat and mass transfer in a NDWCT is in the fill zone, the non-uniformity in the water to air distribution is believed to be the dominant factor in increasing the water temperature [61,64].…”

Section: Eq (2-21)mentioning

confidence: 99%

“…The interference among the towers are also investigated by number of researchers [64,71,83,123,124]. In windless condition, the interference between the towers and adjacent structures is not significant.…”

Section: Multi-tower Interferencementioning

confidence: 99%

“…According to the previous research [26,38,42,64,68,71,131], the realizable k-ε model has been selected in this study. The general term of the governing equations can be expressed as:…”

Section: Governing Equationsmentioning

confidence: 99%

“…Their results indicate the wind reducing the efficiency of the dry cooling tower and increasing the average temperature of the heat exchanger by 5 °C. Al-Waked [39,64] discussed crosswind effects on the performance of both dry and wet towers and found the thermal effectiveness of the cooling towers decrease by more than 30% at crosswind speeds above 10 m/s.…”

Section: Introductionmentioning

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: Cfd Simulationmentioning

confidence: 99%

Section: Eq (2-21)mentioning

confidence: 99%

Section: Multi-tower Interferencementioning

confidence: 99%

“…According to the previous research [26,38,42,64,68,71,131], the realizable k-ε model has been selected in this study. The general term of the governing equations can be expressed as:…”

Section: Governing Equationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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