ORIFICE_PRESS_DROP

Overview

Calculate non-recoverable pressure drop across an orifice plate based on geometry and discharge coefficient.

Excel Usage

=ORIFICE_PRESS_DROP(D, Do, P_one, P_two, C)

• D (float, required): Upstream internal pipe diameter (m)
• Do (float, required): Diameter of orifice at flow conditions (m)
• P_one (float, required): Static pressure upstream of orifice at pressure tap cross-section (Pa)
• P_two (float, required): Static pressure downstream of orifice at pressure tap cross-section (Pa)
• C (float, required): Coefficient of discharge of the orifice (-)

Returns (float): Non-recoverable pressure drop of the orifice plate (Pa)

Examples

Example 1: Standard orifice pressure drop

Inputs:

D	Do	P_one	P_two	C
0.07366	0.05	200000	183000	0.61512

Excel formula:

=ORIFICE_PRESS_DROP(0.07366, 0.05, 200000, 183000, 0.61512)

Expected output:

Result
9069.4747

Example 2: Large orifice high beta ratio

Inputs:

D	Do	P_one	P_two	C
0.1	0.075	150000	145000	0.65

Excel formula:

=ORIFICE_PRESS_DROP(0.1, 0.075, 150000, 145000, 0.65)

Expected output:

Result
2120.2872

Example 3: Small orifice low beta ratio

Inputs:

D	Do	P_one	P_two	C
0.1	0.03	200000	180000	0.6

Excel formula:

=ORIFICE_PRESS_DROP(0.1, 0.03, 200000, 180000, 0.6)

Expected output:

Result
17945.6054

Example 4: High discharge coefficient

Inputs:

D	Do	P_one	P_two	C
0.05	0.03	100000	95000	0.7

Excel formula:

=ORIFICE_PRESS_DROP(0.05, 0.03, 100000, 95000, 0.7)

Expected output:

Result
2931.6918

Python Code

import micropip
await micropip.install(["fluids"])
from fluids.flow_meter import dP_orifice

def orifice_press_drop(D, Do, P_one, P_two, C):
    """
    Calculate non-recoverable pressure drop across an orifice plate based on geometry and discharge coefficient.

    See: https://fluids.readthedocs.io/fluids.flow_meter.html#fluids.flow_meter.dP_orifice

    This example function is provided as-is without any representation of accuracy.

    Args:
        D (float): Upstream internal pipe diameter (m)
        Do (float): Diameter of orifice at flow conditions (m)
        P_one (float): Static pressure upstream of orifice at pressure tap cross-section (Pa)
        P_two (float): Static pressure downstream of orifice at pressure tap cross-section (Pa)
        C (float): Coefficient of discharge of the orifice (-)

    Returns:
        float: Non-recoverable pressure drop of the orifice plate (Pa)
    """
    if D <= 0:
        return "Error: D (upstream diameter) must be positive."
    if Do <= 0:
        return "Error: Do (orifice diameter) must be positive."
    if C <= 0:
        return "Error: C (discharge coefficient) must be positive."
    try:
        result = dP_orifice(
            D=D,
            Do=Do,
            P1=P_one,
            P2=P_two,
            C=C
        )
        return float(result)
    except Exception as e:
        return f"Error: {str(e)}"

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