Flow Rates through multiple Valves

In summary, the flow rates through the valves will be a function of the ratio of the cross-sectional areas of the pipes.
  • #1
CrazyDiamond
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Lets say I have a pump with infinite input. The pump is connected to a valve (V) that has a maximum flow rate capacity of 10 units per second (i.e. 0 to 10 units). This Valve is now connected to two valves in parallel (VA and VB), each identical to the first valve(i.e. max flow rate of 10 units per second each).

Now, my question is - If I set V to 10 units/sec and VA to 8 and VB to 7, what will be the flow rates through each of the valves ? Will the relation be linear (In that case, VA flow: 5.33 and VB flow: 4.67) or is there some other formula ?

On another (not unrelated) note - has anyone here worked with the DURESS-2 system ? Shot in the dark...
:bugeye:
 
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  • #2
CrazyDiamond said:
Lets say I have a pump with infinite input. The pump is connected to a valve (V) that has a maximum flow rate capacity of 10 units per second (i.e. 0 to 10 units). This Valve is now connected to two valves in parallel (VA and VB), each identical to the first valve(i.e. max flow rate of 10 units per second each).

Now, my question is - If I set V to 10 units/sec and VA to 8 and VB to 7, what will be the flow rates through each of the valves ? Will the relation be linear (In that case, VA flow: 5.33 and VB flow: 4.67) or is there some other formula ?

The total flow rate at the outlets must equal the total flow rate at the inlets (conservation of mass). If you flow 10 gpm from valve V, then the valves VA and VB will flow a portion of the 10 gpm (a combined total of 10 gpm) based on their flow coefficients.

For example, if the inlet is flowing 10 gpm, and valve VA is flowing 6 gpm, then valve VB must be flowing 4 gpm.

A simple example using the continuity equation will show that the flow rate through each segment is a function of the ratio of the cross-sectional areas of the pipes.

CS
 
  • #4
Think about resistors in parallel. The valve with the least resistance to flow will get the larger flow, i.e. flow coefficient, inlet piping, exit piping etc...
 

1. What is the purpose of using multiple valves in a flow system?

The main purpose of using multiple valves in a flow system is to control and regulate the flow rate of a fluid. By opening or closing the valves, the flow rate can be adjusted to meet the desired rate for a specific application.

2. Can the flow rate be affected by the number and type of valves used?

Yes, the flow rate can be affected by the number and type of valves used. Different types of valves have different flow characteristics, and having multiple valves in a series or parallel arrangement can also impact the overall flow rate.

3. How do you calculate the total flow rate through multiple valves?

The total flow rate through multiple valves can be calculated by adding up the individual flow rates through each valve. This can be done by using the valve's flow coefficient (Cv) value, which represents the amount of flow that can pass through the valve at a given pressure drop.

4. What factors can impact the flow rate through multiple valves?

There are several factors that can impact the flow rate through multiple valves, including the size and type of valves, the pressure drop across the valves, and the overall system design. Other factors such as fluid viscosity and temperature can also affect the flow rate.

5. How can the flow rate through multiple valves be optimized?

The flow rate through multiple valves can be optimized by selecting the right type and size of valves for the application, minimizing the number of valves in the system, and ensuring proper valve placement and orientation. Regular maintenance and monitoring of the valves can also help to maintain optimal flow rates.

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