Mechanical Engineering - Hydraulics and Fluid Mechanics - Discussion

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

Surface tension should be high because higher surface tension gives low vapor pressure (i.e. No vapor formation takes place of manometric fluid) and also high surface tension prevents the unnecessary rise of fluid in Fluid column due to adhesion during pressure measurement.

@Ahmed.

The Liquid should Stick the walls of tube-- represents high surface tension.

Manometric fluids should have the following properties

* High density (for high-pressure measurement the rise of liquid will be within reasonable limits)
* Low Surface tension.
* 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.
* Chemically Inert.
* Distinct Interface.

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.

Low density is the right option.

Low surface tension and high density.