Conversion of Volumetric Flow to Mass Flow

• Vortex flow meters measure volumetric flow directly (e.g., cubic meters per hour). However, in many applications, the mass flow (e.g., kilograms per hour) or standardized volumetric flow (e.g., cubic meters at standard conditions) is more meaningful.
• Since the density of gases and steam is affected by temperature and pressure, compensation adjusts the measured volumetric flow to calculate the actual mass flow or standardized volumetric flow.

Formula for Mass Flow:

$$\dot{m} = Q \times \rho$$

Where:

• $\dot{m}$: Mass flow rate
• $Q$: Measured volumetric flow rate
• $\rho$: Fluid density (calculated based on temperature and pressure)

How Temperature and Pressure Compensation Works

1. Integrated Sensors:

   • Vortex flow meters equipped with temperature and pressure sensors measure real-time values.
   • These sensors feed data to the flow meter’s transmitter or control system.

2. Real-Time Density Calculation:

   • For gases and steam, the density is calculated using equations of state (e.g., Ideal Gas Law or steam tables) based on the measured temperature and pressure.
   • For liquids, density changes are minimal, and compensation may not be required.

3. Flow Correction:

   • The transmitter uses the density to correct the volumetric flow measurement and provide mass flow or standardized flow.

4. Output Signal:

   • The compensated flow is transmitted to the control system (e.g., via 4-20mA or digital communication protocols such as HART or Modbus).