天大化工原理-英文版课件-Chapter 8-22.ppt

Summarize the performance characteristics of a reciprocating pump;The flow rate can only be controlled by valve on the bypass. 只能用支路阀调节流量。 It is a special performance of a positive-displacement pump.;Other positive displacement pump;FIGURE 8.7 Gear pumps齿轮泵: (a) spur-gear外齿合 pump; (b)internal gear内齿合 pump ;Lobe pump 凸叶转子泵 Screw pump 螺杆泵 2-9 Cam pump 凸轮泵 Vane pump 叶轮（片）泵;8.3 CENTRIFUGAL PUMPS;8. Multistage centrifugal pumps 9. Leakproof pumps 10. Pump priming泵的起动注水(affusion) **11. Piping system characteristic curve **12. Operating point (Duty point) **13. Flow rate control **14. Pump Selection ;Structure of Centrifugal Pumps(离心泵） ; ???????????????????????????????????????????????????????????? ;10;1. Impeller 叶轮, vane or blade 叶片 2. Volute 泵壳，涡壳 3. Shaft gland(stuffing box or mechanical seal) 轴封装置 4. Suction Inlet 吸入口 5. Discharge outlet 排出口;Types of impeller;Impeller types ;Single-suction pump and double-suction pump;15;Single-stage pump and multi-stage pump;Volute;Inducer 导轮;Cutaway view side view;1. Centrifugal pump theory ;Cutaway view side view;FIGURE 8.10 Velocities at entrance and discharge of vanes in centrifugal pump: (a) vectors and vane;;(b) vector diagram at tip of vane. ;2. Head-flow relations for an ideal pump ;The relation between the head(J/kg) and volumetric flow rate is linear. The slope of the head flow rate depend on the sign of tanβ2 and therefore varies with angleβ2.;The figure varies with β2;27;;4. Actual performance of a centrifugal pump;5. Loss of head;6. Performance characteristics特性参数;efficiency;Characteristic curves of a centrifugal pump;Best Efficiency Point (BEP);Maxmum efficiency point(Best Efficiency Point (BEP))-----rated capacity, rated head, rated power, rated efficiency----which is written on the name plate of the pump. 最高效率点-----额定流量，额定压头，额定功率（标注在泵的铭牌上）。;The actual performance characteristics are determined by experiment because of the complex situation in the pump. Experiment scheme of the pump ch