Page 548 - Mechatronics with Experiments

JWST499-Cetinkunt
JWST499-c07
534 MECHATRONICS Printer: Yet to Come October 9, 2014 8:41 254mm×178mm
Valve 1:
Pump
x (t), A (t)
D (t) v1 v1
p
w shaft Q s Q v1
P s P P
Q P v21 v11 v12
r
Relief
valve
P v22
P P
t P t
Tank Tank t Tank
(a)
l 1 l 3 l 6
90° Elbow
T-connector 3 6 d 6 connector
RF 1
l d 1 l 2 d 3 RF 3 RF 6
2 7
RF d 2
2 7 l
d
4 p (Q,l,d, RF, Shape) 7
d RF loss RF 7
l 4
4
5
Shape: Straight,
Tank Tank Tank
T-connector
90 Elbow
(b)
Case (1) Case (2) Case (3) Case (4 ) and (5)
Dp Dp Dp

Time (s) 10 Time (s)
1 2 3 4 5 Time (s)
A x
A v1 v1 A v2 v2
1.0

1 2 3 4 5 Time (s) 1 2 3 4 5 Time (s) 0.5 1.0 x v2 /x max p max Pvr1
(c)
FIGURE 7.92: An example hydraulic circuit: (a) pump, main valve, relief valve, (b) including
the pipe and fitting information for pressure drop estimation, (c) simulated conditions.

loss is estimated as a function of flow rate for different geometric (d, l, bend shapes) and
surface roughness parameters (RF). Hence, the above general functional relationship is
expressed as follows for a given fluid type and nominal operating temperature (i.e., SAE
◦
10 W at 25 C),

p loss = f(Q, l, d, RF, Shape) (7.423)

and this data is given as numerical graphs or data tables by hydraulic fittings and pipe
suppliers (Figure 7.93).