Hello all,
I have notice while using Rota-meter that the bob rotates due to the fluid motion across the same. And the rotational speed is proportional to the mass flow rate of the fluid.
Lets now stick to incompressible fluid - water. The effect of compressibility has its own set of issues to be taken care.
My question here is, since the rotational speed of the bob is dependent on the mass flow rate, whether the inlet flow angularity or the inlet flow swirl has any influence on reading that it is showing (calibration)?
In other words: Does the reading indicated by rotameter changes when the inlet velocity profile (the velocity profile far upstream of the bob) is
laminar with no swirl and laminar with swirl component in it.
Looking for your opinions/ perspectives over this problem.
______ below this line is the refinement to the question after 1st answer____
Thanks to Dr.Aziz. https://www.researchgate.net/profile/Abdul_Jaafar2
Lets consider,
A steady, adiabatic, incompressible flow with friction.
for comparing the two cases consider the mass flow rate is same.
Dear Dr. Aziz,
Before getting onto this question I checked the variation in the reading with changes in the density, it seems that the variation is insignificant provided the density of the bob is at least one order of magnitude higher than the density of the fluid.
Yes, poorly designed bobs have asymmetry and leads to undesired motion of the bob. I need to insist that the rota-meter is designed to work in vertical orientation and also the flow passages and the forces need to be axisymmetric.
As you have correctly pointed out, the effect of heat transfer is totally insignificant and can be eliminated from the discussion.
Lets consider a steady flow for simplicity. And so lets consider that the time rate of change of any parameter is '0' in both the cases.
Thanks for your opinion Dr. Aziz. though it has not answered the question fully, it helped refining the question.
- Badges
- Science topic
- Similar topics
- Engineering
- Thermal Engineering
- Thermofluid
- Fluid Mechanics