That is first to calculate the necessary impeller diameter and rpm, and then to choose a standard impeller which is greater than the necessary one.
在选取轴流式通风机的叶轮直径和转速时，为保证风机消耗的轴功率最小，分析了轴功率的各种影响因素，依据最小轴功率原则和风机经济工作条件，总结出从同类型轴流式通风机中，选择所耗轴功率最小的风机叶轮直径和转速的方法，即首先计算必需的叶轮直径和转速，实际选择时，再取大于必需值的标准叶轮直径和转速。
After cutting the impeller diameter for three times, obtains appropriate diameters.
针对某工程空调水系统调试中发现的冷却水泵匹配电机偏小的问题,经计算分析认为,降低水泵扬程3~4 m可以保证水泵安全运行,采用切割叶轮的方法,三次调整叶轮切割尺寸,得到合适的叶轮直径。
A Toolpath Planning Method for NC Machining of the Hub of an Integrated Impeller
整体叶轮轮毂曲面数控加工刀具轨迹规划方法
The hub of a wheel.
（轮）毂轮子的中心
hob for cycle wheels (incl. coaster-braking hubs)
脚踏车车轮轮毂（包括倒轮刹车轮毂）
The spokes of the wheel diverge from the nub.
轮辐从轮毂向四周分出。
"That could be done with the spokes, not with the hub;
“绑轮辐，可以，绑轮毂，不行。
Moment Rigidity Analysis on Flange of Automotive Hub Bearings
轿车轮毂轴承轮毂凸缘力矩刚性分析
SMALLER DIAMETER OF PIVOT BEARING
轮毂轴承的较小直径端
wheel hub bearing adjusting nut
车轮毂轴承调整螺母
Install rotor on axle hub.
在车轴轮毂上安装转子。
Hub And Bearing Assembly Mounting Surfaces
轮毂轴承组件固定面
A round covering over the hub of the wheel of a motor vehicle.
毂盖机动车轮毂上的圆盖
Two new spokes and a hub must be made.
我必须重新做两根轮辐和一个轮毂。
a radial member of a wheel joining the hub to the rim.
车轮上连接轮缘和毂的放射状的东西。
"The wheels were made like carriage-wheels, the rods on which they were fixed, the parts forming their edges, their rods and the middle points of them, were all formed out of liquid metal."
轮的样式如同车轮。轴，辋，辐，毂都是铸的。
Deformation Analysis on Precision Forging Straight Spur Gear With a Boss
带轮毂直齿圆柱齿轮精锻的变形分析
Application of a Front Wheel Nave of Forklift in Flatbed Trucks
一种叉车前轮轮毂在平板车上的应用
The Analysis on the Stress Field of Aircraft Wheel Hub and the Evaluation on the Life Span of Safety Operation;
航空机轮轮毂应力场分析及安全使用寿命评估
Research on Contour Control Method of CNC Mechanical Polishing Machine for Aluminum Alloy Wheel Hub Surface
铝合金轮毂曲面CNC机械抛光轮廓控制方法研究