Mass Flow Measurement (Non-invasive Measurement)

Why are heat flux sensors important?

Today’s calorimetric mass flow sensors use temperature sensors as the core sensing element. While this type of mass flow sensor is tried and tested, it is nonetheless not the most cost-effective solution. Mass flow sensors can be improved by integrating heat flux sensors into the measurement setup.

Mass flow measurement with gSKIN® Heat Flux Sensors

There are two basic methods for mass flow measurements with heat flux sensors. Here, we describe one of these methods.

1. Install one gSKIN® Heat Flux Sensor. The heat flux sensor measures the heat that passes through its surface in Watts.

2. Install two temperature sensors (Text and Tfluid). Text describes the external temperature, and Tfluid the temperature of the fluid. Both temperatures should be measured close to the heat flux sensor.

3. Determine the heat transfer coefficients of the heat flux sensor to air (Kair-HFS) and the heat conductivity of the heat flux sensor (KHFS).

4. Calculate the heat transfer coefficient of the heat flux sensor to air (KHFS-fluid) by using
KHFS-fluid= Heat flux x (Tfluid – Text)-1 – Kair-HFS – KHFS

5. Determine the parameters a, b, and c of the setup. These parameters are needed for King’s Law
(KHFS-fluid= a + b x vFc)

6. Calculate the velocity of the fluid by applying King’s Law vF= ((KHFS-fluid – a)/b)1/c  Advantages of gSKIN® Heat Flux Sensors:

• Easy to integrate into the measurement setup

• High precision, starting in the mK temperature range

• Cost-effective in comparison to high precision temperature sensors

• Robust design, delivering the same level of resolution as temperature sensors

• Non-invasive measurement of mass flow