# Pressure drop across an array of different nozzles?

• tectactoe
In summary, the conversation discusses calculating the pressure drop in a large flow meter with an array of six nozzles. The velocity of the air, diameter of the flow meter tunnel, and exit diameters of the nozzles are known. The individual tried using Bernoulli's equation with the total combined exit diameter of the nozzles but questions the accuracy of this calculation. They are seeking suggestions and insights from others, particularly HVAC experts.
tectactoe
I have a question about calculating the pressure drop in a large flow meter across an array of nozzles. Basically its inside of a tunnel... air flows in this tunnel until it reaches a "gate" which is blocked off except for six nozzles of different size, which discharge back into an open tunnel...

We know the velocity of the air before the nozzle array (5 m/s), the diameter of the flow meter tunnel (50"), as well as the exit diameter of the six nozzles (6", 3 x 4", 3", and 2").

To be honest, I'm not sure what to do when it comes to the parallel pressure drop through different nozzles. I tried Bernoulli's equation using the total combined exit diameter of the nozzles as my exit point... It gave me about 1.22 inH2O. But I feel like this calculation is wrong because you can not just add up the nozzle exit diameters when in parallel.

Any suggestions?

anyone? any insight would be greatly appreciated.

The HVAC guys might have something about that for their long furnace duct runs.

## 1. What is pressure drop?

Pressure drop is the decrease in pressure of a fluid as it flows through a system or device. It is measured in units of pressure, such as pounds per square inch (psi) or kilopascals (kPa).

## 2. How does pressure drop affect flow rate?

Pressure drop and flow rate are inversely related. As pressure drop increases, flow rate decreases. This is because the fluid must overcome a greater resistance to flow through the system.

## 3. How do different nozzles affect pressure drop?

The shape, size, and design of a nozzle can significantly impact the pressure drop across it. Nozzles with larger diameters and smoother surfaces typically have lower pressure drops compared to smaller or rougher nozzles.

## 4. What factors influence pressure drop across an array of nozzles?

The main factors that influence pressure drop across an array of nozzles include the type and viscosity of the fluid, the velocity of the fluid, the geometry and dimensions of the nozzles, and the overall flow rate through the system.

## 5. How can pressure drop across an array of nozzles be minimized?

To minimize pressure drop across an array of nozzles, it is important to select the appropriate nozzle size and shape for the specific application, ensure a smooth and clean surface of the nozzles, and control the fluid velocity and flow rate. Regular maintenance and cleaning of the nozzles can also help reduce pressure drop.

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