User:Nathanhall78/ENES-100/Project2/CDIO

Problem Statement
Design a cavitation testing apparatus utilizing a closed system; sump pump for water propulsion, PVC tubing for water containment/transportation, and an irrigation control valve (ICV) which will initiate the cavitation process. The section containing the ICV shall also contain a flow-meter and gauge to measure water velocity/volume speed, and water pressure mitigation system which will allow pressure to drop after cavitation process is initiated.

Requirements

 * 1) ICV must close at a rapid speed in order to produce a "water hammer" effect
 * 2) Water system must be airtight and resistant to rapid water pressure change due to cavitation
 * 3) Flow-meter and gauge must adequately relay water velocity or volume throughput without impeding water velocity or volume throughput
 * 4) A clear length of plexiglass tubing shall be attached just above the ICV in order to allow for visual observation of cavitation
 * 5) Water pressure release system shall allow for adequate release of pressure from cavitation/water hammer shock wave
 * 6) Back-flow preventer shall prevent water from backing up PVC tubing at initiation of cavitation

Water Hammer and Cavitation
Water hammer can be caused when a fluid in motion is forced to stop suddenly or change directions drastically. It causes a pressure wave to propagate within the system. [| Math for the wave.]

A .pdf file on "Water Hammer with Column Separation" is found here.

Cavitation is the immediate formation and implosion of tiny bubbles within a fluid after a fluctuation from high pressure to low pressure, and back to high. [| Quick description of cavitation within a control valve.]

Video describing cavitation and vapor pressure of liquids here.

Water Valve Selection

 * This page gives a easy-to-understand breakdown of ICV functionality.
 * This page gives a run-down on various valve types.

This is the ICV to be used in the project.

As noted in various ICV descriptions, ICVs themselves are designed to close at a slow speed in order to prevent water hammer. However, this water hammer shock-wave is what is required to initiate the cavitation desired for the project. As such, the valve needs to be hacked in such a way as to allow for very rapid closing of the valve.

Pressure Relief Section
Based upon the water ram, the pressure relief should be simple. The site here shows a simple diagram. The pressure relief should be modelled after the Fig. 2 (Montgolfier's Ram).

Previous group's design of a water ram system below.


 * 1) Take main stack/valve section in the above photo and move the water release pipe lower on the stack.
 * 2) Attach this stack just above the cavitation observation section of the cavitation system.
 * 3) Reduce the number of "stepdowns" in the PVC stack to reduce turbulence within the stack.

Next Steps

 * 1) Determine ICV close/open speed and if necessary, alter that speed to facilitate water hammer/cavitation.
 * 2) Refine pressure relief system; build from source materials in class or source new material.
 * 3) Begin to marry parts together