Mechanical Engineering - Hydraulics and Fluid Mechanics - Discussion

Low surface tension and high density.

Desirable properties of good manometric liquid should have;
-> Low-freezing point.
-> High boiling point.
-> Non-wetting characteristics.
-> Low surface tension.
-> Chemically inert.
-> Clear visible interface.
-> Ability to maintain density at various temperatures.

Manometric fluids should have the following properties:

* High density ( for high-pressure measurement the rise of liquid will be within reasonable limits).
* Low Viscosity (As high viscosity will slow down the sensitivity or responsiveness of fluid movement).
* Low Vapour Pressure (Because, if Vapour pressure is greater than the fluid pressure to be measured then the problem of cavitation will arise).
* High Boiling point.
* Low Freezing Point.
* Low Surface tension.
* Chemically Inert.
* Distinct Interface.

Low surface tension and high density.

Why low surface tension is required? Please explain in detail.

High density should be the correct answer.

The diameter of manometer will be such that capillarity will not be seen. So what is the point in discussing about surface tension?

The right answer is High surface tension.

It should be high density and low vapour pressure.

Mercury used in manometer and it has high sufrace tention property.