The gasoline nozzle vibrates heavily

This post was last edited by caochaohui on 2012-9-5 at 17:51. We conducted experiments in the laboratory under cold conditions, and it is indeed easy to experience vibration at low flow rates (around 60%). Based on thorough experiments regarding nozzle vibration, the following insights can be offered for reference: 1. At low flow rates, increasing the amount of vapor used for atomization can help prevent vibration; in other words, the vapor volume cannot be adjusted proportionally. For example, at low flow rates, the steam volume can be adjusted to 8%, 10%, or even a higher percentage. 2. When adjusting the nozzle at low load, increase the steam flow while closing the oil circuit valve – more adjustment is made for the steam and less for the oil circuit. Reason for vibration: The performance of nozzles is designed for specific operating conditions; in non-design conditions, only a compromise can be achieved. When the nozzle operates at low load, all the dimensions inside the nozzle appear larger; in other words, pressure cannot be built up, and the velocities of the two phases within the nozzle are both low. The flow regime of the two-phase flow changes, and a stratified flow is likely to form; as it passes through the Laval throat, the steam is on top and the oil is at the bottom. Near the duckbill nozzle, the accumulated oil generates intense vibrations, just like waves crashing against the shore. Significantly increasing the steam volume to maintain the flow velocity of the two-phase flow inside the nozzle can solve this problem. Different nozzles have different adjustment characteristics. What has been said above are my personal opinions. I hope this can be helpful to you.

This post was last edited by caochaohui on 2012-9-5 at 17:51. Additional note: If there is a brief interruption in steam supply or a sudden drop in pressure, oil can enter the steam pipeline. Under certain steam pipeline arrangements, strong vibrations can occur when the steam returns to normal, and this is unrelated to the nozzles nor is it a matter of adjustment. If it’s only the steam pipeline that vibrates, this could be the case. Solution: Reduce the flow valve, temporarily shut down the nozzle, or feed a very small amount. Adjust the amount of vaporized steam appropriately and purge for a while. Ensure the steam volume is set correctly before adding oil. This situation has also occurred in experiments. Sometimes it returns to normal automatically. I hope this can be helpful to you.

The nozzle operating conditions must remain within a certain range; it is not allowed to be below the lower limit or above the upper limit. Whether there is water in the gasoline, whether the pressure is appropriate, whether the steam volume or pressure is within the range set for the nozzle, and the nozzle opening degree—all of these factors play a role. Also, get in touch with the nozzle manufacturers to see if there are any better solutions.

Thank you for the expert advice; I’ll give it a try later. Have you conducted any research on KH-5 nozzles?

This post was last edited by caochaohui on 2012-10-22 at 20:52. No research has been done on KH-5 nozzles. In two-phase flow atomization, it is not easy to achieve complete absence of vibration; there is merely a difference in the magnitude of such vibration. Even if the pipeline does not vibrate, there will still be slight fluctuations in the oil circuit pressure. Pressure fluctuations are a characteristic of two-phase flow atomization; under certain conditions, high-frequency, minor vibrations can turn into low-frequency, severe vibrations, mainly due to significant changes in the two-phase flow pattern inside the nozzle. Mechanical atomization is different; during mechanical atomization, the oil pressure remains very stable. Some burner oil nozzles in regenerators use mechanical atomization. This is just my personal opinion for reference.

When gasoline comes into contact with steam, water hammer can occur. Generally, the amount of vapor generated by gasoline nozzles is very small, so the gasoline can be atomized directly. There is not even a steam control valve; a flow-limiting orifice plate is used directly. You can turn the steam down or up to a high level.

The nozzle vibration frequency should be avoided from synchronizing with the reverse re-vibration frequency