where is the density of water (1000 kg m^3 ),Kis the bulk modulus of
water ( 2 109 Nm^2 ) and Eis the Young’s modulus of the pipe material
(for steel, E 2 1011 Nm^2 ).
The parameter 2 is given by
2 a 0 /gH 0 (13.21)and the head loss coefficient Ksby
Ks(PR)^20 /H 0 (13.22)wherePis the friction loss term in P 0 P^20 (Fig. 12.20) and Ris the head
loss term at the entrance (throttle) to the air vessel, given by
Rk(A/ccAc)^2 /2g, (13.23)in which kis the head loss coefficient at entrance, Ais the area of pipeline,
Acis the throttled (at entrance) area and ccis the contraction coefficient.
SURGES 565
Fig. 13.12 Design charts for an air vessel with Ks0.3