P17080: Heart Pump and Circulatory System
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Preliminary Detailed Design

Table of Contents

Team Vision for Preliminary Detailed Design Phase

The expectation for the Preliminary Detailed Design Phase is to complete theoretical analysis to ensure that the ventricle design is feasible. As well as to conduct Simulink simulations to analyze the ideal outcomes of the created system. Advanced Prototyping will also be done in this phase. The mold for the ventricle will be in construction. Cost analysis for the ventricle housing will be done to select the desired material. Originally the LabVIEW program was expected to be generated during this phase. However, time was re-prioritized towards the theoretical analysis. The currently expected outputs for the LabVIEW program for this phase is a detailed diagram for the design of the code.

Action Items from System Level Design

Completed

In Progress

Updated Design Concept

The vacuum and the air pressure is controlled by the solenoid. The air release is added for safety.

Updated Ventricle

Updated Ventricle

Analysis, Simulations, and Prototyping

Assumptions

Equations

Parameters and General Equations

Parameters and General Equations

Theoretical Analysis

The process of the theoretical analysis was done in four steps.

1. Air Entering Chamber

2. Water Exiting Ventricle

3. Air Exiting Chamber

4. Water Entering Ventricle

Schematic

Schematic

The air entering the chamber was calculated using the Bernoulli equation. The velocity of air was found and then the flow rate was calculated using the known inlet diameter for the laboratory air line. Finally time was found using the flow rate and the volume the air will displace. Using this calculated information it was determined that the pressure from the shop air would be sufficient to open the exit valve.

To open the exit valve the pressure in the chamber must be higher than the pressure on the other side of the valve, 80 mmHg. The charts below show the velocity of air entering the camber and the time it takes for the pressure to change in the chamber. The horizontal line is the pressure required to open the valve.

Analysis of Air Entering Chamber

Analysis of Air Entering Chamber

Next it was determined that the increasing pressure would be sufficient to eject the needed stroke volume for the system. The range for stroke volume is determined by physiological conditions, 60 ml to 100 ml. Calculations for water leaving the chamber were done for minimum, maximum, and average stroke volumes. This is a value that can be regulated in the LabVIEW program to ensure accuracy. The end result shows that the amount of volume needed to be ejected from the ventricle is plausible.

Analysis of Water Exiting Ventricle

Analysis of Water Exiting Ventricle

Then the time for the air to exit the chamber causing a pressure differential to open the entrance valve was calculated. The pressure needed to open the entrance valve is 10mmHg. This calculation was done for all three volumes in using the Bernoulli equation. The horizontal line shows the pressure needed to open the entrance valve and begin allowing water to flow in.

Analysis of Air Exiting Chamber

Analysis of Air Exiting Chamber

Finally, the ability for the pressure differential to allow the needed amount of water to enter the ventricle was analyzed. The horizontal line shows the maximum fill volume. The flowing charts show the ventricle is capable of preforming each of the four tasks. A secondary analysis needs to be done for the force applied to the ventricle and the material properties to determine if the vacuum will cause the material to stretch.

Analysis of Water Entering Ventricle

Analysis of Water Entering Ventricle

Simulation

To better understand the effects that changes in compliance and preload have on the system, a computational model was created using MATLAB Simulink. Using the hydraulic analysis package, a representative model of the circulatory system was created. The Simulink system accounts for all dimensions and losses from tubing, valves, and tanks using real given values. Inputs include the changes to compliance and preload, and the pumping action of the heart, simulated as a sinusoidal wave with a peak value of 5lpm. Results from our simulations acknowledge a decrease in the pulsatility of the wave form as the compliance is increased. Introduction of compliance limits large drops in flow, more accurately modeling a philological waveform
Simulation Schematic of the Simulink Analysis

Simulation Schematic of the Simulink Analysis

Simulink Output High Compliance

Simulink Output High Compliance

Simulink Output LOw Compliance

Simulink Output LOw Compliance

Prototyping

The creation of the ventricle prototype continued during this phase. The Pneumatic Cap Ring and the Hydraulic Ring can be used for both the ventricle design and the adaptation of the previous design. The mold for the silicone ventricle was printed during this phase.

Exploded View of Ventricle Pump

Exploded View of Ventricle Pump

Hydraulic Cap Ring

Hydraulic Cap Ring

Pneumatic Slot Ring

Pneumatic Slot Ring

3D Print of Pneumatic Slot Ring for Preliminary Testing

3D Print of Pneumatic Slot Ring for Preliminary Testing

Pneumatic Ring

Pneumatic Ring

Machining Diagram

Machining Diagram

Ventricle

Ventricle

Ventricle Mold

Ventricle Mold

With the ventricle designed in inventor, we were able to use the built in simulation to show ventricle compression with basic silicone material properties.

Ventricle Stress Analysis

Ventricle Stress Analysis

Bill of Material (BOM)

Cost Analysis of the Raw Material for Heart Pump

Cost Analysis of the Raw Material for Heart Pump

Bill of Materials and Budget

Bill of Materials and Budget

Test Plans

Test Plans Section 1

Test Plans Section 1

Test Plans Section 2

Test Plans Section 2

Diagrams and Flowcharts

System Architecture

Updated System Architecture (RED CIRCLES ARE UPDATED SECTIONS)

Updated System Architecture (RED CIRCLES ARE UPDATED SECTIONS)

Process Diagram

Process Diagram

Controller Diagram and Design

Electrical Setup

Electrical Setup

Wiring Diagram

Wiring Diagram

LabVIEW Flow Chart

Flow Chart of LabVIEW

Flow Chart of LabVIEW

Section 1: Flow Chart of LabVIEW

Section 1: Flow Chart of LabVIEW

Section 2: Flow Chart of LabVIEW

Section 2: Flow Chart of LabVIEW

Risk Assessment

Color Code For Risk Assessment

Color Code For Risk Assessment

Overall Risk Assessment

Overall Risk Assessment

New Risks

New Risks

Updated SME Meeting Information=

Updated SME Information

Updated SME Information

Design Review Materials

PowerPoint for Design Review

Plans for next phase

Plans for Phase 4

Plans for Phase 4

Team Action Items

Three week plan for next phase


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