Sunday, August 30, 2015

Fun Engineering Stuff from BCE - Static Fluid Dynamics

Many process control field devices measure pressure to determine other process variables, such as level and flow. Knowing basics principles of how process instruments work is important. Let's have a little fun with some basic fluid principles.

Question One

Suppose we were to steadily pour a liquid into the leftmost vertical tube until it reaches a mark four inches from the bottom. Given the diameters of the other tubes, how high will the liquid level settle in each when all columns are in a condition of equilibrium (no liquid flowing through any part of the system)?

Now consider the same set of vertical tubes (same diameters, same step heights) connected at the bottom by an inclined pipe. If we were to pour a liquid into the leftmost vertical tube until it reaches a mark two inches from its bottom, how high will the liquid level settle in each column when all columns are in a condition of equilibrium?

Question Two

Which of these tubes will generate the most hydrostatic pressure, assuming they all contain the same type of liquid at precisely the same (vertical) height?

(Attribution for questions to Tony R. Kuphaldt.)