CV_NOISE_GAS_2011

This function estimates aerodynamic control-valve noise for gas service using the IEC 60534-8-3 (2011) method. It computes the A-weighted sound pressure level at 1 m from the downstream pipe wall based on flow rate, pressures, thermophysical properties, valve coefficient, and piping geometry.

The reported noise level is expressed in decibels using the logarithmic sound-pressure relation:

L_p = 20\log_{10}\left(\frac{p_{\mathrm{rms}}}{p_0}\right)

where p_0=2\times10^{-5} Pa is the reference sound pressure. Optional coefficients such as attached-fitting recovery factors and outlet temperature can be provided to refine the prediction.

Excel Usage

=CV_NOISE_GAS_2011(m, p_in, p_out, t_in, rho, gamma, mw, kv, d, di, t_pipe, fd, fl, flp, fp, rho_pipe, c_pipe, p_air, rho_air, c_air, an, stp, t_out, beta)

m (float, required): Mass flow rate of gas through the control valve (kg/s)
p_in (float, required): Inlet pressure of the gas before valves and reducers (Pa)
p_out (float, required): Outlet pressure of the gas after valves and reducers (Pa)
t_in (float, required): Inlet gas temperature (K)
rho (float, required): Density of the gas at the inlet (kg/m³)
gamma (float, required): Specific heat capacity ratio (dimensionless)
mw (float, required): Molecular weight of the gas (g/mol)
kv (float, required): Metric Kv valve flow coefficient (m³/hr)
d (float, required): Diameter of the valve (m)
di (float, required): Internal diameter of the pipe before and after the valve (m)
t_pipe (float, required): Wall thickness of the pipe after the valve (m)
fd (float, required): Valve style modifier (dimensionless)
fl (float, optional, default: null): Liquid pressure recovery factor without attached fittings; provide this or flp (dimensionless)
flp (float, optional, default: null): Liquid pressure recovery factor with piping geometry factor (dimensionless)
fp (float, optional, default: null): Piping geometry factor (dimensionless)
rho_pipe (float, optional, default: 7800): Density of the pipe wall material (kg/m³)
c_pipe (float, optional, default: 5000): Speed of sound in the pipe wall material (m/s)
p_air (float, optional, default: 101325): Standard atmospheric pressure (Pa)
rho_air (float, optional, default: 1.2): Density of air at standard conditions (kg/m³)
c_air (float, optional, default: 343): Speed of sound in air (m/s)
an (float, optional, default: -3.8): Constant for gas noise calculation
stp (float, optional, default: 0.2): Strouhal number for gas noise calculation
t_out (float, optional, default: null): Outlet gas temperature (K)
beta (float, optional, default: 0.93): Correction factor for gas properties

Returns (float): LpAe1m - A-weighted sound pressure level [dB], or an error message (str) if input is invalid.

Example 1: IEC example-style gas noise calculation with attached fittings only

Inputs:

m	p_in	p_out	t_in	rho	gamma	mw	kv	d	di	t_pipe	fd	flp	fp	rho_pipe	rho_air
2.22	1000000	720000	450	5.3	1.22	19.8	77.85	0.1	0.2031	0.008	0.296	0.792	0.98	8000	1.293

Excel formula:

=CV_NOISE_GAS_2011(2.22, 1000000, 720000, 450, 5.3, 1.22, 19.8, 77.85, 0.1, 0.2031, 0.008, 0.296, 0.792, 0.98, 8000, 1.293)

Expected output:

91.677

Example 2: Lower pressure-drop gas noise scenario

Inputs:

m	p_in	p_out	t_in	rho	gamma	mw	kv	d	di	t_pipe	fd	fl
1.5	800000	700000	300	3	1.3	20	50	0.08	0.15	0.006	0.3	0.8

Excel formula:

=CV_NOISE_GAS_2011(1.5, 800000, 700000, 300, 3, 1.3, 20, 50, 0.08, 0.15, 0.006, 0.3, 0.8)

Expected output:

80.131

Example 3: Higher flow and pressure-drop gas noise scenario

Inputs:

m	p_in	p_out	t_in	rho	gamma	mw	kv	d	di	t_pipe	fd	fl	flp	fp
3	1200000	600000	500	6	1.25	18	100	0.12	0.25	0.01	0.25	0.75	0.8	0.95

Excel formula:

=CV_NOISE_GAS_2011(3, 1200000, 600000, 500, 6, 1.25, 18, 100, 0.12, 0.25, 0.01, 0.25, 0.75, 0.8, 0.95)

Expected output:

97.5904

Example 4: Low-flow gas noise scenario

Inputs:

m	p_in	p_out	t_in	rho	gamma	mw	kv	d	di	t_pipe	fd	fl
0.5	500000	400000	293	1.2	1.4	28.96	20	0.05	0.1	0.004	0.4	0.85

Excel formula:

=CV_NOISE_GAS_2011(0.5, 500000, 400000, 293, 1.2, 1.4, 28.96, 20, 0.05, 0.1, 0.004, 0.4, 0.85)

Expected output:

73.4581

Python Code

Show Code

import math
from fluids.control_valve import control_valve_noise_g_2011 as fluids_control_valve_noise_g_2011

def cv_noise_gas_2011(m, p_in, p_out, t_in, rho, gamma, mw, kv, d, di, t_pipe, fd, fl=None, flp=None, fp=None, rho_pipe=7800, c_pipe=5000, p_air=101325, rho_air=1.2, c_air=343, an=-3.8, stp=0.2, t_out=None, beta=0.93):
    """
    Calculate the A-weighted sound pressure level for gas flow through a control valve per IEC 60534-8-3 (2011).

    See: https://fluids.readthedocs.io/fluids.control_valve.html#fluids.control_valve.control_valve_noise_g_2011

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

    Args:
        m (float): Mass flow rate of gas through the control valve (kg/s)
        p_in (float): Inlet pressure of the gas before valves and reducers (Pa)
        p_out (float): Outlet pressure of the gas after valves and reducers (Pa)
        t_in (float): Inlet gas temperature (K)
        rho (float): Density of the gas at the inlet (kg/m³)
        gamma (float): Specific heat capacity ratio (dimensionless)
        mw (float): Molecular weight of the gas (g/mol)
        kv (float): Metric Kv valve flow coefficient (m³/hr)
        d (float): Diameter of the valve (m)
        di (float): Internal diameter of the pipe before and after the valve (m)
        t_pipe (float): Wall thickness of the pipe after the valve (m)
        fd (float): Valve style modifier (dimensionless)
        fl (float, optional): Liquid pressure recovery factor without attached fittings; provide this or flp (dimensionless) Default is None.
        flp (float, optional): Liquid pressure recovery factor with piping geometry factor (dimensionless) Default is None.
        fp (float, optional): Piping geometry factor (dimensionless) Default is None.
        rho_pipe (float, optional): Density of the pipe wall material (kg/m³) Default is 7800.
        c_pipe (float, optional): Speed of sound in the pipe wall material (m/s) Default is 5000.
        p_air (float, optional): Standard atmospheric pressure (Pa) Default is 101325.
        rho_air (float, optional): Density of air at standard conditions (kg/m³) Default is 1.2.
        c_air (float, optional): Speed of sound in air (m/s) Default is 343.
        an (float, optional): Constant for gas noise calculation Default is -3.8.
        stp (float, optional): Strouhal number for gas noise calculation Default is 0.2.
        t_out (float, optional): Outlet gas temperature (K) Default is None.
        beta (float, optional): Correction factor for gas properties Default is 0.93.

    Returns:
        float: LpAe1m - A-weighted sound pressure level [dB], or an error message (str) if input is invalid.
    """
    try:
      # Validate required inputs
      required_params = [m, p_in, p_out, t_in, rho, gamma, mw, kv, d, di, t_pipe, fd]
      if not all(isinstance(x, (int, float)) for x in required_params):
        return "Error: All required parameters must be numeric."

      if any(not math.isfinite(x) for x in required_params):
        return "Error: All required parameters must be finite numbers."

      if m < 0:
        return "Error: Mass flow rate (m) must be non-negative."
      if p_in <= 0 or p_out <= 0:
        return "Error: Pressures must be positive."
      if t_in <= 0:
        return "Error: Inlet temperature (t_in) must be positive."
      if rho <= 0:
        return "Error: Gas density (rho) must be positive."
      if gamma <= 0:
        return "Error: Specific heat capacity ratio (gamma) must be positive."
      if mw <= 0:
        return "Error: Molecular weight (mw) must be positive."
      if kv <= 0:
        return "Error: Valve flow coefficient (kv) must be positive."
      if d <= 0:
        return "Error: Valve diameter (d) must be positive."
      if di <= 0:
        return "Error: Pipe internal diameter (di) must be positive."
      if t_pipe <= 0:
        return "Error: Pipe wall thickness (t_pipe) must be positive."
      if fd <= 0:
        return "Error: Valve style modifier (fd) must be positive."

      # Validate optional numeric inputs with defaults
      other_numeric_params = [rho_pipe, c_pipe, p_air, rho_air, c_air, an, stp, beta]
      if not all(isinstance(x, (int, float)) for x in other_numeric_params):
        return "Error: All numeric parameters must be numeric."

      if any(not math.isfinite(x) for x in other_numeric_params):
        return "Error: All numeric parameters must be finite numbers."

      if rho_pipe <= 0 or c_pipe <= 0 or p_air <= 0 or rho_air <= 0 or c_air <= 0:
        return "Error: Material property values must be positive."

      # Validate optional parameters without defaults
      if fl is None and flp is None:
        return "Error: Either fl or flp must be provided."
      if fl is not None:
        if not isinstance(fl, (int, float)) or not math.isfinite(fl) or fl <= 0:
          return "Error: fl must be a positive finite number if provided."
      if flp is not None:
        if not isinstance(flp, (int, float)) or not math.isfinite(flp) or flp <= 0:
          return "Error: flp must be a positive finite number if provided."
      if fp is not None:
        if not isinstance(fp, (int, float)) or not math.isfinite(fp) or fp <= 0:
          return "Error: fp must be a positive finite number if provided."
      if t_out is not None:
        if not isinstance(t_out, (int, float)) or not math.isfinite(t_out) or t_out <= 0:
          return "Error: Outlet temperature (t_out) must be a positive finite number if provided."

      try:
        # Prepare the function call with all parameters
        kwargs = {
          'm': m, 'P1': p_in, 'P2': p_out, 'T1': t_in, 'rho': rho, 'gamma': gamma, 'MW': mw,
          'Kv': kv, 'd': d, 'Di': di, 't_pipe': t_pipe, 'Fd': fd, 'FL': fl,
          'rho_pipe': rho_pipe, 'c_pipe': c_pipe, 'P_air': p_air,
          'rho_air': rho_air, 'c_air': c_air, 'An': an, 'Stp': stp, 'beta': beta
        }

        # Add optional parameters if they are provided
        if flp is not None:
          kwargs['FLP'] = flp
        if fp is not None:
          kwargs['FP'] = fp
        if t_out is not None:
          kwargs['T2'] = t_out

        result = fluids_control_valve_noise_g_2011(**kwargs)
        if not math.isfinite(result):
          return "Error: Function returned non-finite value."
        return result
      except Exception as e:
        return f"Error: Failed to compute gas noise: {str(e)}"
    except Exception as e:
      return f"Error: {str(e)}"

Online Calculator

m *

Mass flow rate of gas through the control valve (kg/s)

p_in *

Inlet pressure of the gas before valves and reducers (Pa)

p_out *

Outlet pressure of the gas after valves and reducers (Pa)

t_in *

Inlet gas temperature (K)

rho *

Density of the gas at the inlet (kg/m³)

gamma *

Specific heat capacity ratio (dimensionless)

mw *

Molecular weight of the gas (g/mol)

kv *

Metric Kv valve flow coefficient (m³/hr)

d *

Diameter of the valve (m)

di *

Internal diameter of the pipe before and after the valve (m)

t_pipe *

Wall thickness of the pipe after the valve (m)

fd *

Valve style modifier (dimensionless)

Liquid pressure recovery factor without attached fittings; provide this or flp (dimensionless)

flp

Liquid pressure recovery factor with piping geometry factor (dimensionless)

Piping geometry factor (dimensionless)

rho_pipe

Density of the pipe wall material (kg/m³)

c_pipe

Speed of sound in the pipe wall material (m/s)

p_air

Standard atmospheric pressure (Pa)

rho_air

Density of air at standard conditions (kg/m³)

c_air

Speed of sound in air (m/s)

Constant for gas noise calculation

stp

Strouhal number for gas noise calculation

t_out

Outlet gas temperature (K)

beta

Correction factor for gas properties