144
S. N. Mahottamananda et al.
3 Results and Discussion
3.1 Effect of Number of Inlet Tangential Ports and Their
Angle on Liquid Sheet Breakup Length
In a plug type swirl injector, unstable growth of sinuous waves on the surface of
liquid sheet causes liquid sheet breakup. The breakup length of liquid sheet L b is
measured as the distance from the exit of injector to where the liquid sheet breaks up
along the spray axis, illustrated in Fig. 5. For every injection pressure, more than 20
photos of the spray are taken at different runs and are used to calculate the average
value of L b .
The determination of breakup length L b of plug type swirl injector liquid sheet in
the axial direction is expressed as [6],
L b = L cos
θ
2
(1)
The effect of number of inlet tangential ports on breakup length L b is presented in
Fig. 6. The trend of decreasing breakup length with increasing pressure is observed.
Higher injection pressure is resultant in higher axial velocity component. Higher
resultant axial velocity component increases the tendency of earlier disintegration of
the liquid film [7]. A decrease in liquid sheet breakup length L b leads to a decrease
in the length of the combustion chamber. It is also observed that for all injection
pressures, SW1 injector configuration gave 43–49% lesser breakup length compared
to SW3 injector configuration. The effect of inlet tangential port angle on liquid sheet
breakup length is shown in Fig. 6. It is observed that for each injection pressure SW1
injector gave 7–11% lesser breakup length compared to SW2 injector configuration.
This is because of SW2 injector is having higher tangential port angle compared to
Fig. 5 Definitions of spray cone angle and breakup length
S. N. Mahottamananda et al.
3 Results and Discussion
3.1 Effect of Number of Inlet Tangential Ports and Their
Angle on Liquid Sheet Breakup Length
In a plug type swirl injector, unstable growth of sinuous waves on the surface of
liquid sheet causes liquid sheet breakup. The breakup length of liquid sheet L b is
measured as the distance from the exit of injector to where the liquid sheet breaks up
along the spray axis, illustrated in Fig. 5. For every injection pressure, more than 20
photos of the spray are taken at different runs and are used to calculate the average
value of L b .
The determination of breakup length L b of plug type swirl injector liquid sheet in
the axial direction is expressed as [6],
L b = L cos
θ
2
(1)
The effect of number of inlet tangential ports on breakup length L b is presented in
Fig. 6. The trend of decreasing breakup length with increasing pressure is observed.
Higher injection pressure is resultant in higher axial velocity component. Higher
resultant axial velocity component increases the tendency of earlier disintegration of
the liquid film [7]. A decrease in liquid sheet breakup length L b leads to a decrease
in the length of the combustion chamber. It is also observed that for all injection
pressures, SW1 injector configuration gave 43–49% lesser breakup length compared
to SW3 injector configuration. The effect of inlet tangential port angle on liquid sheet
breakup length is shown in Fig. 6. It is observed that for each injection pressure SW1
injector gave 7–11% lesser breakup length compared to SW2 injector configuration.
This is because of SW2 injector is having higher tangential port angle compared to
Fig. 5 Definitions of spray cone angle and breakup length