Page 427 - Air and Gas Drilling Manual

34 15
Tee
,
1 826 6 .
.
0 426
19 47)
.
.
519 67
2 723 3 .
,
.
2 607 lb/ft 3 504 41 . (. Chapter 9: Aerated Fluid Drilling 9-31
Tee
The approximate velocity of the aerated fluid flow just downstream of the Tee and
valves is
P g T r
Q g Q m
P sr T g
V Tee
D sr 2
4
Substituting the values of Q g, Q m, P g, P , T g, T r, and D into the above equation
sr
sr
gives
1 826 6 . 504 41
,
.
19 47)
.
(. 0 426
2 723 3 . 519 67
.
,
V Tee
0 469)
(. 2
4
V Tee 75 91 ft/sec
.
The approximate pressure change, ∃ P , through the two valves and Tee is
Tee
2
V Tee
∃ P Tee Tee K Tee 2 K v
2 g
where K Tee is the minor loss flow resistance coefficient for the Tee,
K v is the minor loss flow resistance coefficient for a valve.
Using the dimensions of the Tee, Figure 8-5 can be used to obtain the approximate
minor loss resistance coefficient of the Tee. This is
K Tee 27
The approximate minor loss resistance coefficient for the valve is [18]
.
K v 02
Substituting the values of Tee, K Tee, K v, V Tee, and g into the above equation gives