Mass flow rate through a regulator

In summary, the conversation discusses the use of a canister filled with compressed air at 4500psi and a single stage pressure regulator to reduce the outlet pressure to 850psi. The resulting flow from the regulator is used in a divergent nozzle to create a thrust force capable of lifting a small mass. The mass flow rate is not constant and decreases as the canister empties, following a logarithmic pattern. The question is whether there is a way to calculate the mass flow rate and thrust for the system with a regulator involved. It is mentioned that the system can be shut off remotely once the output pressure drops below 850psi and that the mass flow rate will be constant as long as the tank pressure is above the required inlet supply
  • #1
gl96
2
0
Hi,

We have a canister at a set pressure (4500psi) full of compressed air. A single stage pressure regulator is fitted to the canister that reduces the outlet pressure to 850psi. The flow from the regulator is then used in a divergent nozzle to create a thrust force capable of lifting a small mass (2-3kgs). I understand that the mass flow rate is not constant and have obtained graphs using thrust equations for 4500psi with no regulator. The graphs take into account the fact that the mass flow rate and pressure decrease as the canister empties and from the graphs this shows a logarithmic decrease in the thrust generated. Is there a way to calculate the mass flow rate (and therefore the thrust) for the system with a regulator involved?

After the output pressure drops below the 850psi we would shut off the system remotely.
 
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  • #2
As long as the tank pressure is above the required inlet supply pressure to the regulator at the regulator's 850 psi set pressure then the mass flow will be constant and equal to the value shown on your graph when the tank pressure is equal to the set pressure of your regulator, assuming the combined regulator and nozzle flow coefficient is the same as the nozzle coefficient used for the tank flow calculation without the regulator.
 

1. What is mass flow rate through a regulator?

The mass flow rate through a regulator is the amount of mass that passes through the regulator per unit time. It is typically measured in kilograms per second (kg/s) or grams per second (g/s).

2. How is mass flow rate through a regulator calculated?

The mass flow rate through a regulator is calculated by multiplying the density of the fluid by the volumetric flow rate. This can be represented by the equation: m_dot = ρ*Q, where m_dot is the mass flow rate, ρ is the density, and Q is the volumetric flow rate.

3. What factors affect the mass flow rate through a regulator?

The mass flow rate through a regulator can be affected by several factors, including the size of the regulator orifice, the pressure difference across the regulator, the viscosity of the fluid, and the temperature of the fluid.

4. How does a regulator control the mass flow rate?

A regulator controls the mass flow rate by adjusting the size of the orifice, which in turn affects the pressure difference across the regulator. This allows for a more precise control of the flow rate and can be achieved through mechanical or electronic means.

5. What are some common applications for measuring mass flow rate through a regulator?

Measuring the mass flow rate through a regulator is important in many industries, such as chemical processing, food and beverage production, and HVAC systems. It is also commonly used in research and development, particularly in experiments involving fluids.

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