A numerical investigation of air-cooled steam condenser performance under windy conditions

[摘要] ENGLISH ABSTRACT: This study is aimed at the development of an efficient and reliable method of evaluating theperformance of an air-cooled steam condenser (ACSC) under windy conditions, usingcomputational fluid dynamics (CFD). A two-step modelling approach is employed as a resultof computational limitations. The numerical ACSC model developed in this study makes useof the pressure jump fan model, amongst other approximations, in an attempt to minimize thecomputational expense of the performance evaluation. The accuracy of the numerical modelis verified through a comparison of the numerical results to test data collected during fullscale tests carried out on an operational ACSC. Good correlation is achieved between thenumerical results and test data. Further verification is carried out through a comparison toprevious numerical work. Satisfactory convergence is achieved for the most part and the fewdiscrepancies in the results are explained. The effect of wind on ACSC performance at ElDorado Power Plant (Nevada, USA) is investigated and it is found that reduced fanperformance due to distorted flow at the inlet of the upstream fans is the primary contributorto the reduction in performance associated with increased wind speed in this case. An attemptis subsequently made to identify effective wind effect mitigation measures. To this end theeffects of wind screens, solid walkways and increasing the fan power are investigated. It isfound that the installation of an appropriate wind screen configuration provides a usefulmeans of reducing the negative effects of wind on ACSC performance and an improved windscreen configuration is suggested for El Dorado. Solid walkways are also shown to bebeneficial to ACSC performance under windy conditions. It is further found that ACSCperformance increases with walkway width but that the installation of excessively widewalkways is not justifiable. Finally, increasing the fan power during periods of unfavourableambient conditions is shown to have limited benefit in this case. The model developed in thisstudy has the potential to allow for the evaluation of large ACSC installations and provides areliable platform from which further investigations into improving ACSC performance underwindy conditions can be carried out.

[发布机构] Stellenbosch University