Effect of Temperature on Bubble Tube Sensitivity

Introduction:
A bubble tube is a device that is used to measure the flow rate of liquids in pipelines. It is based on the principle of flow measurement by the use of a differential pressure sensor. The bubble tube consists of two tubes connected at the bottom by a U-tube. One of the tubes is connected to the pipeline while the other tube is open to the atmosphere. When the liquid flows through the pipeline, the pressure difference between the two tubes causes bubbles to form at the bottom of the U-tube. The rate of bubble formation is proportional to the flow rate of the liquid.

Effect of Temperature:
The sensitivity of a bubble tube is affected by various factors, including temperature. As the temperature of the liquid increases, the sensitivity of the bubble tube decreases. This is due to the following reasons:

1. Viscosity: The viscosity of the liquid decreases with an increase in temperature. This reduces the resistance to flow, leading to an increase in the flow rate. As a result, the rate of bubble formation in the bubble tube also increases. However, the change in bubble rate is not proportional to the change in flow rate due to the effect of temperature on the sensitivity of the bubble tube.

2. Thermal Expansion: The thermal expansion of the liquid also affects the sensitivity of the bubble tube. As the temperature of the liquid increases, its volume increases, leading to a change in the pressure difference across the bubble tube. This change in pressure difference affects the rate of bubble formation and hence the sensitivity of the bubble tube.

Conclusion:
In conclusion, the sensitivity of a bubble tube decreases with an increase in temperature. This is due to the effect of temperature on the viscosity of the liquid and the thermal expansion of the liquid. Therefore, it is important to consider the effect of temperature when using a bubble tube for flow measurement.