净断面积 meaning in English
net sectional area
Examples
- For hoods with shutters in four sides , the results show : 1 ) the hoods positively placed boards are called hoods used for venting airflow ; hoods negatively placed boards are called hoods used for leading airflow ; 2 ) among the hoods used for venting airflow , the most effective hoods should have positive declining angle value of 30 , the ratio 4 of areas between the four windward faces and the gular section ( fy / fj = 4 ) , the value of b range from 70 mm to 120 mm and the value of b / h range from 0 . 5 to 0 . 6 ; 3 ) the most effective hoods should have negative declining angle value of 60 , the ratio 4 of areas between the four windward faces and the gular section ( fy / fj = 4 ) , the value of b range from 100 mm to 170 mm ( the optimum value is 120 mm ) and the value of b / h range from 1 . 4 to 2 . 2 ( the optimum value is 2 . 0 )
对于四面设百叶型风帽，计算表明: l )正装倾斜挡板的百叶型风帽可认为是排风型风帽，倒装挡板倾斜的百叶型风帽可认为是进风型风帽; 2 )排风型风帽中，挡板正装30 ” 、风帽四个迎风面的有效面积fy和风管净断面积fj的比值( fy肠)为4 、挡板宽度b在70inln到120inln之间、板间距比值陇在0 . 5到0 . 6的百叶型风帽排风效果最好; 3 )进风型风帽中，挡板倒装装60 “ 、风帽四个迎风面的有效面积和风管净断面积的比值( fy例)为4 、挡板宽度b在100咖到170mm之间( 120mm为最佳) 、板间距比值陇在1 . 4到2 . 0的进风型风帽( b爪= 2 . 0为最佳)的百叶型风帽进效果最好。