Can a larger pressure release port decrease pressure loss over time?

[sionglx]

Greetings All,

I have a question regarding Pressure Loss through a Small hole vs Time.

My simplified scenario is that I have a vessel filled with Sea Water Pressured up to 70 bar. At the outlet valve, there is a pressure release port of 5mm dia which is able to relieve the pressure down to 3 bar is a matter of 3 seconds.

To describe the scenario better, only after the pressure has been released can the valve be opened fully.

Question:- How long will it take if i increase the Pressure release port to say 10mm. I would like to make the pressure release even faster. Is there a direct relation of rate of pressure release to size of hole??

Am unable to find anything regarding this topic.

There is a similar thread but cannot make anything out of the response there.

https://www.physicsforums.com/showthread.php?t=171660&highlight=pressure+loss+hole+time

MAny Thanks & Regards.

 

[mfb]

It will depend on your setup. If the pressure drop in your port happens over a short length (<5mm), it should be a reasonable assumption that mass flow is proportional to the area. In that case, doubling the diameter should give 1/4 the original time. This assumes that the opening process does not need any time...

 

[sionglx]

It will depend on your setup. If the pressure drop in your port happens over a short length (<5mm), it should be a reasonable assumption that mass flow is proportional to the area. In that case, doubling the diameter should give 1/4 the original time. This assumes that the opening process does not need any time...

mfb,

thank you for your quick reply. i would have to confirm that the port length is very short.
COuld you please quote some reference where you get the assumption of mass flow rate and area?
Or if there is a formula i could refer to?

BR,

 

[mfb]

For short ports, the exit velocity is determined by the pressure difference (and the shape of the port), but not the area. Every textbook about fluid mechanics should cover that.

 

[PJC01]

I can provide a response to this question based on the principles of fluid dynamics and pressure release mechanisms. First, let's understand that pressure loss over time is influenced by several factors, including the size and shape of the release port, the viscosity of the fluid, and the pressure within the vessel. In general, a larger pressure release port can decrease pressure loss over time, but the extent of this decrease depends on the other factors mentioned above.

In your scenario, increasing the pressure release port from 5mm to 10mm will likely result in a faster pressure release. This is because a larger port allows for a greater volume of fluid to be released at once, reducing the pressure within the vessel more quickly. However, the exact amount of time saved will also depend on the viscosity of the sea water and the pressure within the vessel.

In terms of a direct relationship between the rate of pressure release and the size of the hole, there is a general trend that increasing the size of the hole will result in a faster pressure release. However, this relationship is not linear and may vary depending on the specific conditions of the system. Additionally, other factors such as the design of the pressure release mechanism and any obstructions or turbulence in the flow path can also affect the rate of pressure release.

In conclusion, while increasing the size of the pressure release port can generally decrease pressure loss over time, the exact amount of time saved will depend on various factors and may not have a direct relationship with the size of the hole. Further experimentation and analysis would be needed to determine the optimal size for the pressure release port in your specific scenario. I hope this helps clarify the topic for you.