| name | neqsim-noise-screening |
| version | 0.1.0 |
| description | Educational valve and line aerodynamic-noise indicator that estimates a screening sound-pressure level from gas mass flow, pressure drop, and density using a public IEC 60534-8 style energy approach. USE WHEN: a task needs a public, screening-level noise indicator and an action/high flag for a gas valve or restriction before detailed IEC 60534-8 noise prediction. |
| last_verified | 2026-06-18 |
| requires | {"python_packages":[],"java_packages":[],"env":[],"network":[]} |
Noise Screening
Use this skill for public, educational aerodynamic-noise screening of a gas valve or line restriction. It estimates a sound-pressure-level indicator from the mass flow, pressure drop, and density using an open energy-based approach, so an agent can flag a potential noise problem before detailed IEC 60534-8 prediction.
When to Use
- When a user asks whether a gas valve or restriction is likely to be noisy.
- When an agent needs a quick action/high noise flag for screening.
- When examples must run without confidential valve trim or vendor noise data.
Inputs
mass_flow: gas mass flow in kg/s.pressure_drop: pressure drop across the restriction in bar.inlet_density: inlet gas density in kg/m3.sound_speed: speed of sound in m/s (provide this, or temperature and molar mass).specific_heat_ratio: ratio of specific heats k, default 1.3.temperature: gas temperature in K (used to estimate sound speed).molar_mass: gas molar mass in g/mol (used to estimate sound speed).
Outputs
vena_contracta_velocity_m_s: estimated velocity at the restriction.mach_number: velocity divided by the speed of sound.internal_sound_power_level_db: internal sound power level (re 1 pW).estimated_spl_1m_dba: screening sound-pressure level at 1 m.noise_warning: ok, action, or high.assumptions: public assumptions used by the placeholder model.
Engineering Method
The Python class ValveNoiseModel uses a public energy-based aerodynamic-noise approach:
- the vena-contracta velocity uses
v = sqrt(2 * dP / rho).
- the speed of sound uses the provided value or
c = sqrt(k * R * T / M).
- the mechanical stream power uses
W_m = 0.5 * mdot * v^2.
- the acoustic power uses
W_a = min(0.01, eta_f * Mach^3) * W_m.
- the sound power level uses
L_W = 10 log10(W_a / 1 pW) and a fixed transmission loss converts it to a 1 m sound-pressure level.
This is an educational screening indicator, not a full IEC 60534-8-3 prediction. It uses a generic acoustic efficiency and a fixed transmission loss with no valve style, trim, pipe schedule, distance correction, or frequency weighting. It is not a replacement for validated noise prediction, vendor noise data, and qualified acoustic review.
Python Usage Pattern
from noise_screening import ValveNoiseModel
model = ValveNoiseModel()
result = model.evaluate(
mass_flow=12.0,
pressure_drop=40.0,
inlet_density=35.0,
temperature=310.0,
molar_mass=19.0,
)
print(result.mach_number)
print(result.estimated_spl_1m_dba)
print(result.noise_warning)
Related NeqSim Functionality
For validated valve behaviour, redirect to existing NeqSim classes:
neqsim.process.equipment.valve.ThrottlingValve — flow-vs-Cv valve and pressure-drop response that defines the noise duty.neqsim.process.equipment.valve.ControlValve — control valve with characteristic and controller coupling.
Full aerodynamic-noise prediction follows IEC 60534-8-3. This skill is a public noise triage layer that decides when to invoke detailed valve and noise tools.
Validation Checklist
Common Mistakes
| Symptom | Cause | Fix |
|---|
| SPL looks too precise | Treated indicator as IEC result | Use it only for screening |
| Mach off | Sound speed from wrong gas | Provide molar mass and temperature |
| Wrong magnitude | Mass flow in kg/h not kg/s | Use kg/s |
Limitations
- Screening indicator only, not IEC 60534-8-3 prediction.
- No valve style, trim, pipe schedule, or frequency content.
- Fixed transmission loss and generic acoustic efficiency.
References
