The material chosen
for the fabrication of pintle injector is SS-304. The Injector is made of two
parts. the outer body and the inner pintle. The pintle is screwed inside the
outer body so that the pintle opening distance can be varied for the different
experiments.
Figure 6 .2-D drawing of the injector with
dimensions in millimeter.
In the outer body of
the injector. two inlets are placed diametrically opposite to each other. The
diameter of these inlets are 5 mm each. One inlet leads to the outer annular
gap and the second one to the center of the injector. The pintle angle is 25°.
Figure 7. Different views of the injector
Figure 8. Sectional view of the outer body
Atomization was seen insufficient for the combustion of
liquid kerosene and Liquid Oxygen. For kerosene to burn, the mean drop size
should be less than 30 to 50 microns.
The challenge with the injector was to achieve
the proper propellant distribution through the annular orifice.
Pintle opening
(mm)
|
Pressure
(Kg/cm2)
|
Time
(s)
|
Flow rate Kg/s
|
Area of Discharge (mm2)
|
Velocity (m/s)
|
Reynolds Nu
|
Webber nu
|
0.55
|
1.5
|
10
|
0.132
|
30.549
|
4.31
|
2360.438
|
140.003
|
0.63
|
1.5
|
7.6
|
0.156
|
34.992
|
4.46
|
2798.799
|
171.837
|
0.95
|
1.5
|
9.5
|
0.172
|
52.766
|
3.25
|
3079.86
|
137.991
|
1.33
|
1.5
|
9.8
|
0.185
|
73.873
|
2.51
|
3324.432
|
114.841
|
1.6
|
1.5
|
9.8
|
0.189
|
88.869
|
2.13
|
3397.698
|
99.716
|
1.89
|
1.5
|
7.9
|
0.197
|
104.977
|
1.88
|
3544.577
|
91.872
|
Annular gap data is given below:
The spray from a pintle injector with water and air can be seen below:
Radial flow can be seen below:
