declining angle meaning in English
衰减角
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。 - For shelters , the results show : 1 ) to reduce the raining drops entering into the inlet and to decrease the influence of the vortex , the declining angle of 45 is recommended for the shelters ; 2 ) it is better to choose those shelters which are longer 100 mm ~ 200 mm than the height of the inlets , as they may protect the room from rain
对于单侧百叶风口的挡雨板，计算表明: 1 )为了防止雨水随空气流入自然进风口，并且使风口尽量少受涡流区的影响，建议选用倾斜角度为45 “的挡雨板; 2 )建议选用长度比风口高度长100mm - - 200 “的挡雨板，可以较好的避免挡雨板过短将雨水带入室内和过长影响风口进风的情况。 - For shutters , the results show : 1 ) according to the formula p = , the theoretical value of is calculated by the effective velocity of the flow , and its engineering value is calculated by the arriving velocity of the flow , the relationship between the theoretical value of and its engineering value is 2 ) the smaller value of declining angle will result in the smaller pressure loss and smaller outlet velocities . as a result , the declining angle of 30 掳 or less is recommended in some places which need small wind velocity , such as broadcasting studio and library , and the declining angle of 45 掳 or less is recommended in places which need big wind velocity , such as cinema and office ; 3 ) the larger value of ratio between the wide of the shutter b and the space between two boards h ( b / h ) will result in the larger pressure loss and smaller outlet velocities . the range of b / h from 0 . 8 to 2 . 0 and the optimum value 1 . 2 is recommended ; 4 ) the range of b from 10 mm to 50 nun and the optimum value 40 mm is recommended ; 5 ) the proper thickness of the boards 8 of the shutters is 1 . 5 mm ; 6 ) cuneiform boards should replace the rectangle inlet boards of the shutters in order to obtain better ventilation
数值模拟采用fluent软件，计算结果用excel进行处理，通过对大量数值工况进行数值模拟计算，结果表明：对于单侧百叶风口，计算表明： 1 )对于公式p = ( ~ 2 ) 2 ，的理论计算值中定义为流体流经百叶风口内部时的速度，即有效速度，而工程上常使用流体的来流速度来计算，计算表明，的理论计算值与工程应用值的关系为( _ (理论) ) ( _ (工程) ) = 0 . 813 ； 2 )当来流速度一定时，挡板倾斜角度越小，压力损失越小、出口速度越小；因此在要求进口风速比较小的场所，如播音室、图书馆等，宜采用挡板角度30的百叶风口；在要求进口风速比较大的场所，如电影院、办公室等，百叶挡板的角度应选45 ； 3 )当来流速度一定时，百叶挡板的挡板宽度b与挡板间距h的比值b h越大，压力损失越大，出口速度越小，计算表明，鉴于压力损失、出口风速、板间形成涡流区的大小，百叶挡板的b h值取0 . 8到2 . 0之间， b h = 1 . 2为最佳值； 4 )当来流速度一定时，在计算的条件下，当百叶挡板宽度b = 40mm时，百叶挡板的阻力系数最小，考虑到涡流区等的影响，建议选用10mm b 50mm的百叶挡板；西安建筑科技大学硕士学位论文5 )百叶挡板的厚度取为1 . sinln为好; 6 )百叶挡板的入口侧可选用具有倾斜度的楔形挡板来代替矩形挡板，利用其较好的导流作用，可得到更好的出流效果。