Calorimetric mass flow measurement # Calorimetric Mass Flow Measurement: A short review

This short review gives the reader a good overview of calorimetric or thermal mass flow measurement.

## Introduction to Calorimetric Mass Flow Measurement

### Definition of thermal mass flow sensors

Thermal mass flow meters or sensors perform direct mass flowrate of gases and liquids measurements. Indeed, mass flow measurement is independent from fluctuations of viscosity, density, temperature and pressure. Those systems are commonly used to monitor or control processes where mass flow is a key parameter. Consequently, thermal flow meter are standard instruments used in Chemical Engineering to control for instance the amount of reagents being added to the reaction vessel or to evaluate the relative masses of unreacted ingredients that could interfere with the reaction.

## Heat flux Sensor Integration Calorimetric Mass Flow Meters

### Mass flow measurement with gSKIN® Heat Flux Sensors

There are two methods for calorimetric mass flow measurements with heat flux sensors. Here, we’ll focus on describe only one of those two methods for thermal mass flow measurement.

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

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

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

• 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

• Determine the parameters a, b, and c of the setup. These parameters are needed for King’s Law:

(KHFS-fluid= a + b x vFc)

• Calculate the velocity of the fluid (vF) by applying King’s Law:

vF= ((KHFS-fluid – a)/b)1/c

### Advantages of gSKIN® Heat Flux Sensors

• Miniature & Compact heat flux sensors
• Non-invasive measurement of thermal mass flow
• 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