P13465: Water Table
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Systems Design

Table of Contents


In-place Water Tunnels

These projects provide examples of water tunnels of varying sizes. Everything is included from large closed throat tunnels for cavitation to small open channel (free surface) tunnels for academic labs.

Relevant Articles

Concept Development (generation, improvement, selection)

Team meeting notes from the initial concept generation/brainstorming:

MSD Meeting 4 Dec 12- Concept Generation Ideas

9 Dec 12 Concept Assessment Meeting Notes

Concepts were selected using a variety of methods in which concept ideas were ranked against important functions and parameters. These are manifested in the link below.

Preliminary Concept Selection Worksheet

Functional Decomposition

The link below shows the function decomposition for the water table. The functional decomposition represents specific tasks that the project must perform in order to accomplish the end goal. Note that besides constraints, these function trees offer no information about how the given tasks should be completed.

Water Table Functional Decomposition

The water table function decomposition can be downloaded by clicking: Download Water Table Functional Decomposition .vsd File

Feasibility Analysis


Preliminary test of electrolysis have been carried out to determine the feasibility of use for this application. The notes of the test are captured in the links below. The video clips were taken during the specified conditions.

12/15/2012 Experimentation


Electrolysis Feasibility Test 1

Video Clips:

Electrolysis 12V w/o NaHCO3 -- Electrolysis 12V w/ NaHCO3 -- Electrolysis 20V w/ NaHCO3 -- Electrolysis 24V w/ NaHCO3

12/28/2012 Experimentation


Electrolysis Feasibility Test 2

Video Clips:

Electrolysis 24V w/ 1Tsp NaHCO3 -- Electrolysis 24V w/ 2Tsp NaHCO3 -- Electrolysis 24V w/ 3Tsp NaHCO3 -- Electrolysis 24V w/ 4Tsp NaHCO3

Additionally, a pulsing circuit is going to be implemented into the electrolysis design. The initial thought is to pulse the power delivered to the electrodes which will allow the user to follow the flow more closely. A preliminary schematic along with the transient analysis for that schematic is shown below.

Students will be able to vary the pulse through the use of a potentiometer (variable resistor), this is not shown in the schematic below. The circuit was initially designed for an on/off cycle of ~10seconds (5seconds off / 5seconds on)

Preliminary Schematic for Pulsing Circuit

Transient Analysis Results


The following spreadsheet shows the calculations to find the power requirements for the pump to overcome gravity in the system. The calculations do not take into account losses due to piping, but show that a 1/3 horsepower pump that meets the flow rate requirements will work.

Pump Calculations

Pump Calculation Excel Spreadsheet

Test Specimen

Helicoil configurations and magnetic holders were analyzed. The magnets to use would need to be extremely strong to meet the test specs or force on the test specimen, but they are achievable.

Test Specimen Holder Feasibility

Microbubble Rise Time

Calculations were made to determine microbubble rise time to confirm the feasibility of using electrolysis microbubbles as a flow visualizer. The calculations show that the rise time poses no concern.

Microbubble Rise Time Calculations

Flow Analysis

CFD analysis was completed in order to verify that flow is uniform across the test section. The analysis was tested at 1 ft/s. It was concluded that the flow at the test section meets specification and is uniform within .1 ft/s.

Flow Analysis (CFD)

Systems Architecture

A preliminary design was developed based on concept selection. The preliminary design contains a layout/map of the water table design with design concepts. Detailed drawings of the design concepts are present in the "Detailed Design" section. The system model, system flowchart, and timing diagram can be found in the links below.

System Model

System Flowchart

Timing Diagram

Risk Assessment

A risk assessment of the project was developed to plan for a variety of possible risk items that may occur during the project. This allows the team to be prepared for possible problems the project may have in the future and to think about how the team will work through it in advanced. In the link below a variety of risk items are categorized with corresponding importance and actions to minimize risk as well as who is responsible for each risk. The risk management document will be continually updated throughout MSD. This risk management sheet is the latest version before the Systems Design Review (last updated 1/2/13).

Risk Assessment

Preliminary Budget

At this stage a preliminary budget has been developed. Many of the costs are variable and subject to change during the detailed design review. Overall, it appears like the project will come in over-budget.

Preliminary Budget

Systems Design Review

The Systems Design Review presentation can be viewed by clicking the link below. This presentation discusses the customer needs and specifications, systems model, risk assessment, and project progress. The Systems Design Review took place on 1/9/13 from 5:30pm - 7:30pm.

Systems Design Review Presentation

The notes from the Systems Design Review can be accessed in the link below.

Systems Design Review Feedback and Action Items

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