ENGG 2230 Lecture Notes - Lecture 17: Horsepower, Max Q, Vapor Pressure

• School: University of Guelph
• Department: Engineering
• Course: ENGG 2230
• Professor: Bill Van Heyst

Document Summary

Plot curves of q (flow rate) versus h (head of pump: for a gi(cid:448)e(cid:374) pu(cid:373)p a(cid:374)d at a (cid:272)o(cid:374)sta(cid:374)t rotatio(cid:374)al shaft speed (cid:858)(cid:374)(cid:859, ca(cid:374) also i(cid:374)(cid:272)lude effi(cid:272)ie(cid:374)(cid:272)y (cid:858) (cid:859) A parabola is fitted through the pump curve: =(cid:1853)+(cid:1854)(cid:1843)(cid:2870) = 0 at q = 0 and = 0 at q = qmax. Is the head required at the pump inlet to keep the liquid from boiling. (cid:1842)(cid:1845)=(cid:3017)(cid:3034) +(cid:3118)(cid:2870)(cid:3034) (cid:3017)(cid:3034: (cid:1842) is vapour pressure, (cid:1842)(cid:1845)=(cid:3017)(cid:3034) (cid:1858) (cid:3017)(cid:3034, (cid:1858) is the friction loss head between the pump and the reservoir. If the pu(cid:373)p is pla(cid:272)ed at a height of (cid:858)z(cid:859) a(cid:271)o(cid:448)e a reser(cid:448)oir (cid:449)ith at(cid:373)ospheri(cid:272) pressure at the free surface then the energy equation becomes. Output variables: net head (h), brake horsepower (bhp) Important parameters: flow rate (q), impeller diameter (d), shaft speed (n) Other parameters: density ( ), viscosity ( ), surface roughness ( )