Fouling Detection (Non-invasive Measurement)


How to detect fouling with gSKIN® Heat Flux Sensors?

Fouling is a process that creates a layer on the component where it is deposited (e.g. furring in a water pipe). This layer increases the absolute thermal resistance of the component. The increase of the absolute thermal resistance can be measured by combining a heat flux sensor with two temperature sensors.

Fouling is a process that creates a layer on the component where it is deposited (e.g. furring in a water pipe). This layer increases the absolute thermal resistance of the component. The increase of the absolute thermal resistance can be measured by combining a heat flux sensor with two temperature sensors.

Advantages of gSKIN® Heat Flux Sensors:

  • Small heat flux sensor with high sensitivity, easily integrated into the application setups

  • Non-invasive measurement technique for determining fouling

  • Flexible, easy to mount on pipes and boilers

Illustrative image: mounting of a sensor on a pipe

Absolute Thermal Resistance Calculation

The absolute thermal resistance between the T1 and T2 are defined by

Rth = ∆T / HF

where
Rth = Absolute thermal resistance, in K/W
HF = Heat Flux, in W
∆T = Temperature difference, in

The two figures on the right display a common structure in heat exchangers. As soon as fouling starts to deposit on the heat exchanger fins, the Absolute Thermal Resistance Rth starts to increase. When ∆T and HF are measured, this change can be detected.

While the principle is explained for fouling, it can also apply to any other depositions that need to be detected. Other common examples are ice formation (e.g. on plane wings), and algae formation (e.g. on ship hulls).

Absolute Thermal Resistance without Fouling

Absolute Thermal Resistance with Fouling