Study on the discharge coefficient of wind-driven naturally ventilated Chinese solar greenhouses  

作　　者：Jingfu Zhang Shumei Zhao Zhiwei Liu Yanfeng Li Youyu Li Zilong Fan Tao Ding 

机构地区：[1]College of Water Resources and Civil Engineering,China Agricultural University,Beijing,100080,China [2]Infrastructure Construction Department,China Agricultural University,Beijing,100080,China [3]Tibet Academy of Agricultural and Animal Husbandry Sciences,Lhasa,851418,China

出　　处：《Building Simulation》2024年第9期1541-1556,共16页建筑模拟（英文）

基　　金：funded by the Natural Science Foundation of China(U20A2020);the Key Research and Development Program of Xinjiang Uygur Autonomous Region(2022A02005-1);the Basic Research Funds of Public Welfare Research Institutes of Xinjiang Autonomous Region.

摘　　要：The Chinese solar greenhouse(CSG)is a prevalent feature in agricultural practices within China.Nevertheless,the regulation of natural ventilation within this architectural structure remains suboptimal.Consequently,the development of a natural ventilation model becomes imperative for the effective management of the greenhouse environment.Of particular significance within these models is the consideration of the discharge coefficient as a pivotal parameter.Conducting a multi-case investigation into the variable-dependent discharge coefficient is crucial for both practical application and model advancement.This research delved into the impact of various factors,including the upper-lower vents area ratio(A_(up)/A_(low)),vent-greenhouse area ratio(A_(low)/A_(greenhouse)),lower vent position height(h/H),the incident angle of the external wind,and altitude,on the discharge coefficient(C_(d))of CSG.A CFD model was developed for a scaled CSG with validation conducted through field experiments and wind tunnel tests.Results indicated a 61.6%reduction in C_(d)on average corresponding to an 80%decrease in A_(up)/A_(low).C_(d)levels remained consistent following the attainment of an A_(up)/A_(low)ratio of 1.0.Besides,there was an average increase of 52.5%in C_(d)levels for every 0.09 decline in h/H,attributed to the blocking effect of the cover.Moreover,the ventilation rate and the pressure coefficient difference were utilized to construct a model of C_(d)pertaining to greenhouse design and ventilation operation,exhibiting a notable accuracy level of R^(2)=0.95.Furthermore,the blocking effect of higher h/H was relieved as the incident angleθdecreased under the windward conditions.The increase in A_(up)/A_(low)and the decrease in A_(low)/A_(greenhouse)were identified as crucial factors contributing to the growth of C_(d)under leeward conditions.Ultimately,the high-altitude environment led to a rise in C_(d)levels in contrast to the low-altitude region.The increasing rate of C_(d)correlated positively with A_(low)/A_(greenhouse

关 键 词：Chinese solar greenhouse discharge coefficient area ratio position height wind direction ALTITUDE 

分 类 号：TU834[建筑科学—供热、供燃气、通风及空调工程]