RESULTS AND DISCUSSION
Air pressure in the blow tube
Figure 3 represents air pressure in the blow tube for 4 bar and 6 bar reservoir pressures. Considering only the 4 bar reservoir pressure case, peak pressure observed is 379538.2 Pa, which is 274.5% more than atmospheric pressure. And peak pressure observed is not equal to 4 bar, which can be attributed to the frictional losses in the blow tube and in the pipe connecting blow tube and air reservoir. Fig. 3 Variation of air pressure with time in the blow tube.
This peak pressure is observed at 8.8 ms after the actuation of the valve. It means that valve will be fully opened at 8.8 ms after the actuation. Since the time period of valve opening is 150 ms, it is clear that there is a mechanical …show more content…
Numerical results show that there is a sudden increase in the pressure when the pulse enters the bag. A similar trend is observed in experimental pressure values as well. For the location P1, peak pressure achieved from the experimental and numerical analysis are 423.6 Pa and 444.6 Pa, respectively. As the jet of air enters the bag, due to its porous structure, the high momentum jet will continuously travel out of the bag from the upper parts of the bag (location P1). Due to this high-velocity permeation of the jet, there is drop in the pressure within the bag below the atmospheric pressure thus developing negative pressure in this region, as indicated by experimental result (Fig. 5a). This effect is not observed in the numerical result. And, it can also be related to the suction of secondary air by creation of negative zone in the region between orifice and bag entrance …show more content…
In case of 6 bar reservoir pressure, for the constant volume of the reservoir, more amount of air is compressed and stored in the reservoir. Therefore the amount of air entering the bag for 6 bar reservoir pressure is greater than that for 4 bar reservoir pressure (confirmed from Fig. 4 also). And pulse is entering with high velocity. This causes larger negative pressure to develop at the location P1 of the bag and more pressure is build up at the locations P3 and P4 of the bag (Fig.
Air pressure in the blow tube
Figure 3 represents air pressure in the blow tube for 4 bar and 6 bar reservoir pressures. Considering only the 4 bar reservoir pressure case, peak pressure observed is 379538.2 Pa, which is 274.5% more than atmospheric pressure. And peak pressure observed is not equal to 4 bar, which can be attributed to the frictional losses in the blow tube and in the pipe connecting blow tube and air reservoir. Fig. 3 Variation of air pressure with time in the blow tube.
This peak pressure is observed at 8.8 ms after the actuation of the valve. It means that valve will be fully opened at 8.8 ms after the actuation. Since the time period of valve opening is 150 ms, it is clear that there is a mechanical …show more content…
Numerical results show that there is a sudden increase in the pressure when the pulse enters the bag. A similar trend is observed in experimental pressure values as well. For the location P1, peak pressure achieved from the experimental and numerical analysis are 423.6 Pa and 444.6 Pa, respectively. As the jet of air enters the bag, due to its porous structure, the high momentum jet will continuously travel out of the bag from the upper parts of the bag (location P1). Due to this high-velocity permeation of the jet, there is drop in the pressure within the bag below the atmospheric pressure thus developing negative pressure in this region, as indicated by experimental result (Fig. 5a). This effect is not observed in the numerical result. And, it can also be related to the suction of secondary air by creation of negative zone in the region between orifice and bag entrance …show more content…
In case of 6 bar reservoir pressure, for the constant volume of the reservoir, more amount of air is compressed and stored in the reservoir. Therefore the amount of air entering the bag for 6 bar reservoir pressure is greater than that for 4 bar reservoir pressure (confirmed from Fig. 4 also). And pulse is entering with high velocity. This causes larger negative pressure to develop at the location P1 of the bag and more pressure is build up at the locations P3 and P4 of the bag (Fig.