Ask the Experts- Thermal Mass Flow Meters its Working Principle

In the same fashion of our Ask the Expert blogs, today we are here to describe Thermal Mass Flow Meters and its Working Principle, to our ingenious readers.

Let’s start with thermal fluids and its meaning-

The term ‘Thermal Fluid’ refers to heat and fluid, while fluid consists of liquid, gas, and vapors.  Density, pressure, and volume play a crucial role in the thermal fluid. Heat transfer is the major activity that occurs while thermal fluid flows in different mediums.

Thermal Mass Flow Meters

Generally, there are three types of flow meters with various industrial applications. Thermal mass flow meters are also known as thermal dispersion or immersible mass flow meters. It consists of a range of devices for the measurement of the total mass rate of a fluid. Another type of thermal dispersion is the capillary –tube flow meter. Further, Mass Flow Controllers (MFC) is the third type of immersible mass flow meter. It represents the 2% of global flow meters sales.

How does Thermal Mass Flow Meter Works

It requires thermal properties of the fluid to measure the flow rate of the fluid. In conventional flow meters, heat is passed to the heater of the sensor. During this process, some of this heat approaches the flowing fluid in the pipe or duct. Heat is lost according to the increasing flow. Here, thermal flow meters are used to measure fluid flows. 

Thermal properties of the fluid and flow meter design, decides the amount of total heat loss during the process. The thermal properties of the fluid may change according to the temperature and pressure, but these changes are comparatively small in most of its applications. Fluids with constant thermal properties remain stable during the actual operations and thermal mass flow meters can be used to measure the mass flow of the fluid. Although, thermal properties of the fluid don’t have significant effects on the measurement process, but somehow, it depends on the fluid compositions.

Hence, this was how thermal mass flow meters works and thermal properties of the fluid holds an important place in the process of flow measurement.