project descriptionedge.rit.edu/content/p09021/public/p09021 design review 2... · web viewtubing...

KGCOE MSD Technical Review AgendaMeeting Purpose: To review the detailed design proposal to ensure design adequacy.

Materials to be Reviewed:

Customer Specifications rev.5Engineering Analysis rev.2Risk Analysis rev.2BOM and Budget rev.1

Meeting Date: February 13, 2009Meeting Location: 09-4435Meeting time: 10 a.m. - 12 a.m.

Timeline:Meeting Timeline

Start Time Topic of Review Required Attendees

10:00 Introductions, Review Agenda Day, Phillips, Wellin

10:02 Design Review 1 Action Items Day, Phillips, Wellin

10:03 System Design and BOM Day, Phillips, Wellin

10:15 Fluids Analysis – Electrical Simulation, Results Day, Phillips, Wellin

10:35 Blood Tank – Bubble Rise Time, Fluid Extraction Day, Phillips, Wellin

10:40 Water Bath – Heat Transfer Day, Phillips, Wellin

10:45 Tubing – Heat Transfer Day, Phillips, Wellin

10:50Automated Resistance - Linear motor’s force approximation Day, Phillips, Wellin

11:00 Compliance Tank – Arterial Tank Dimensioning, Electrical Equivalent Model Day, Phillips, Wellin

11:15 Custom LVAD Connection Day, Phillips, Wellin

11:20 System Drain – Saline Flush Day, Phillips, Wellin

11:25 Pressure, Flow, and Temperature Sensors and DAQ Day, Phillips, Wellin

11:50 LabView Front Panel Concept Day, Phillips, Wellin

11:55 Wrap-up Day, Phillips, Wellin

P09021 Hydraulic VAD Test Loop System Level Design Review

Project Description

Project Background:The left ventricle is responsible for pumping blood out to the body and for a person with heart disease might not be strong enough. A left ventricular assist device (LVAD) can be surgically implanted to give the heart the boost it needs. RIT is developing a magnetically levitated axial flow LVAD.

Past senior design projects have worked on creating a durability tester for the LVAD, and a centering magnet device. Additionally two projects have focused on developing hemodynamic flow simulation systems.

Problem Statement:The main goal of this project is to create and construct a flexible system that can be run and operated from a user interface on LabView and allow the creation of flow and pressure curves generated from LVAD devices. The system will be able to test LVAD device both with and without Pulsatile Ventricular Simulator (PVS) with fluids and blood.

Objectives/Scope:1. Collect and process data to generate pressure and flow curves for static system which is automatically adjusted.3. Capable of extracting fluids while running in order to determine damage to blood caused by LVAD.3. Collect and process data to generate pressure and flow curve for dynamic system which is a scaled model of the physiological circulatory system working with a PVS.

Deliverables: Functional, partially biocompatible Left

Ventricular Assist Device test loop.

Pressure, Temperature, and Flow characteristic curves for static and dynamic systems.

Expected Project Benefits: Aide in development of magnetically levitated

axial flow LVAD by helping to characterize the amount of assistance which is generated, finding the optimal pressure assist, and determining pumps impact on blood.

Reinforcing the bioengineering program at RIT.

Core Team Members: Jonathan Klein – Project Manager Kyle Menges – Technical Lead Nguyen Dinh Vu – Technical Lead Christine Lowry – Design Engineer (ME) Chris Stein – Design Engineer (ME) Priyadarshini Narasimhan – EE Julie Coggshall – ISE

Strategy & Approach

Assumptions & Constraints:1. Understand the pressure, volume, flow rate, and

temperature of the physiological circulatory system.

2. Working with an existing steady state VAD closed loop, the team will be able to begin their analysis before designing a loop with the LV Simulator.

3. Proposed Budget: $2,000 - $3,0004. Minimize test loop volume and simplistic design

due to blood expenses and risk of damage/ clotting.

Issues & Risks:o Available Resources

Functional Pulsatile Ventricular Simulator

o Blood Issues Certification Purchasing and storage Locations and use

o Project Understanding by team Bio compatibility Physiological Simulation Electrical Needs

January 16, 2009 2

Project # Project Name Project Track Project Family

P09021 Hydraulic VAD Test Loop

Assistive Devices and Bioengineering

Artificial Organ Engineering

Start Term Team Guide Project Sponsor Doc. Revision

2008-2 Dr. Day Dr. Day 3.0


P09021: VAD Test Loop – Customer Needs

Need# Needs to

Importance (Scale: High,

Medium, Low)

1 Able to incorporate LVAD R2 pump into Test Loop High

2 Able to run with and without Pulsatile Ventricular Simulator High

3 Simulate phyiological properties of the human body (i.e., temperature, resistance, compliance) High

4 Consist of Biocompatible components to minimize blood damage High

5 Closed loop system that cannot leak High

6 Generate Pressure and Flow curves at associated temperatures High

7 Operate using multiple fluids (water, water/glycerin mixture, blood) High

8 Extraction of fluid samples cannot interrupt test while running High

9 Within budget High

10 Safe for operators, observers and surrounding environment High

11 Correlate existing pump functionality test with collected data Medium

12 Easy to fill and drain fluids Medium

13 Volume cannot exceed that of blood bag Medium

14 Test device needs to be self contained and portable Medium

15 Easy to maintain and calibrate device Medium

16Minimal comprehension of the system's functionality is needed to operate (friendly user interface, preferably LabVIEW) Medium

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KGCOE MSD DR1 Action ItemsMeeting Purpose: To review the following material in order to gain input based off of attendees’ experience.

Materials Reviewed: 26 Page packet included: 1 page summary, needs and specifications, Pugh charts, and sub-system descriptions. PowerPoint Visual Aide.

Attendees: Julie Coggshall –IE, Priya- EE, Chris- ME, Kyle- ME, Nguyen- ME, Christine- ME, Jon- IE, Dr. Day- Customer and faculty guide, David Gomez and members of LVAD team- work for Dr. Day, Dr. Doolittle- Professor Head for the School of Life Sciences, Dr. Phillips- EE Professor, Prof. Wellin- ME.

Meeting Date: 16 Jan 09

Item # Description Responsible Comments

A001 Create Quick Connect Design IE-Jon Valve and non-valve connections

A002 Reservoir Calculations – Air Bubbles ME-Nguyen Calculated bubble rise time

A003Temperature Control – Heating Tank, find out what changes are in the human body with regards to temperature?

ME-Chris Heating element, water bath

A004 Should we use the flow sensors Dr. Day has? EE-Priya Yes

A005Pressure Sensor Selection – are resolution, output format and frequency response appropriate? Will sensor trap blood?

EE-Priya Use Bleed port

A006 Select Resistance Generation Method – research automated clamp valve ME - Kyle Automate clamp

A007 Compliance Tank Analysis – Do we need two tanks? EE-Priya Do not need

A008Compliance Tanks – What are the clinical comparisons for the compliance values, what about different disease states.

ME-Christine, Nguyen

Ideal value ~2 mL/mm Hg, range varies for different diseases

A009 Blood removal - Look into self healing membrane. ME - Chris Disposable syringe,

extended connection

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Electrical Equivalent SimulationPurpose: Analyze the effect of the venous compliance tank (is it really necessary?)

Figure 1. – Complete system including both capacitors (compliance tanks)

If a resistor represents the resistance in the system, pressure is represented by the voltage in a circuit and the current is the flow rate, a model using electric components can be used to represent the test

loop. and are the resistors representing the resistance of tubing while is the variable resistor used to vary the resistance in the system so as to achieve desired flow and pressure curves. The 2mF capacitor is the arterial compliance and since it has the units of ml/mmHg the capacitor is in micro farads to follow the units of compliance as opposed to l/mmHg in which case the capacitor value would be 2F. The 50mF capacitor also follows the units of the venous compliance which has the value of 50ml/mmHg. A square wave representing the LVAD and PVS, LVAD is indicated the 1V base voltage and the 100V is the PVS mimicing the left ventricle's pumping. The pulse width is 360ms as it because it best models the duration of a single heart beat and the period was set for 60 beats per minute.

Calculation of the total resistance in Figure 1=>

Frequency of the circuit =

The impedance of capacitor = 1

2πfC

Therefore the total resistance of the above circuit=>

0.51Ω//50mF =

11

0.51+ 1

1j2π 50 e−3

= (0.4972 - j0.07966) Ω

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(0.4972 - j0.07966)Ω in series with 0.51Ω, 13 Ω, 0.51 Ω = 0.4972 - j0.07966 + 0.51+0.51+13

= (14.5173 – j0.07966) Ω

(14.5173 – j0.07966) Ω // 2mF=

11

0.51+ 1

1j2π 50 e−3

= (14.5172 - j0.067101) Ω

(14.5172-j0.067101) Ω in series with 0.51 Ω = 14.5172-j0.067101 + 0.51 = (15.0272 – j0.067101) Ω

Time

0s 0.5s 1.0s 1.5sV(R1:2) -I(R2) V(C1:1) V(V1:+)

-50

0

50

100

(93.507m,3.0701)

(20.779m,320.801m)

(49.351m,87.605)

(9.0909m,9.853)(286.957m,3.4120)

(286.957m,6.6473)

(286.957m,96.610)

Figure 2.: Figure shows the simulation of figure 1

Figure 3. – System without venous capacitor (compliance tank).

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The total resistance of Figure 3=>

Total impedance in figure 1 – 0.51 Ω //50mF = (15.0272 – j0.06710) Ω - (0.4972 - j0.07966) Ω

= (14.53 – j0.01256) Ω

Time

0s 0.5s 1.0s 1.5sV(R1:2) -I(R2) V(V1:+)

-50

0

50

100

(49.351m,87.435)

(9.0909m,9.844)

(243.478m,7.1310)

(256.522m,96.363)

Figure 4.: Figure shows the simulation of figure 3

Table 1: Results to the simulation of figure 1 and 3 showing the voltage at the nodes near each capacitor, the total current and rise times for both arterial and venous.

Figure 1 was the schematic used to simulate the test loop with an arterial capacitor and venous capacitor while figure 3 was the schematic used to simulate the test loop without a venous tank. Figure 2 shows the results of the simulation of figure 1 and figure 4 shows the results of the simulation of figure 3. Table 1 shows the results of both simulations in a table form with the voltages at the nodes near the arterial and venous capacitance. It also shows the total current in the loop and also the rise time of both the arterial and venous capacitance. Besides this, the table compares the results obtained with and without the venous capacitor. It shows that by removing the venous capacitor, the voltage at the node

January 16, 2009 12


near the arterial capacitor decreases slightly since the total current in the loop has increased. The rise time is going to be the same since the capacitor value is not changed. So since there is no drastic change in the voltage at the arterial tank, it will not be required to have the venous. To keep the current, or the rate of flow of the liquid, the variable resistor should be varied.

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Fluids Analysis

**Refer to Introduction to Fluid Mechanics by Fox et. Al for all equations, tables and figures referenced for the fluids analysis.

Properties:

Blood viscosity=0.0027 Ns/m2

Blooddensity=1060 kg /m3

Re=ρ v Dμ

( P1

ρ+α1

v12

2+g z1)−( P2

ρ+α 2

v22

2+g z2)=h¿ eq8.29

Assumptions:

The assumptions that were chosen for the fluids analysis include:

Laminar Flow Incompressible Flow Steady State

The fact that blood is a non-Newtonian fluid and that our calculated Reynolds number was 3,936 indicates that there will be some variability between theoretical calculations and the actual pressures and flow measured within the system. Introducing the PVS into the system creates a non-steady condition, and therefore we decided to analyze the system at the maximum desired flow rate for physiological simulation (6 Liters/minute). Under the assumed conditions, the PVS and LVAD both contribute a negative head loss to the system using eq. 8.29, and therefore will benefit the system in terms of pressure loss.

Minor Losses:

To find friction factor f a VBA code (written by Mr. John Wellin) was used. The code requires an input of the Reynolds number and roughness of the pipe/tubing to perform several iterations in order to determine the friction factor based on the Moody Diagram.

January 16, 2009 14


hlm=f LD

v2

2eq8.34

hlm=K v2

2eq8.40a

For Bend in tube at bottom of loop Table 8.4 was used for 90o elbows (worse case)

For all changes in diameter, including the LVAD Reducer, Fig. 8.14 was used to find the appropriate loss coefficients (Kc, Ke).

For Quick Connects a loss coefficient of K=0 was used as provided in the data sheet from the manufacturer.

The Blood loop and Glycerin water solution loop were analyzed for head losses due to the tubing, connections, tanks and other affects of the system. From our calculations both systems will be able to run and have enough pressure to complete the circuit even with the associated head losses. For the fluids analysis of the Glycerin loop steady state was assumed any variations from this assumption while using the PVS can be accounted for in testing.

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Blood Loop


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Physiological Loop


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Fb

Fdmg

2R


Bubble Rise Time

Abstract: this is an analysis to figure out how much time needed for a bubble to reach the surface of liquid. It can be applied for dimensioning the blood tank.

Scheme / given information:

- blood viscosity µ=0.0027 at 100°F- blood density ρblood=1060 kg/m3- air density ρair=1.177 kg/m3 at 100°F

- bubble volume

Vol=43π R3

- buoyancy force Fb=ρblood gVol- drag force Fd=6πμbloodRV- gravity force mg- velocity of fluid inside the tubing Vfluid=0.79 m/s

Assumption: bubbles is sphere-shape, temperature is constant at 100˚F, the bubble rises vertically.

Analysis:

ma=Fb−Fd−mg⇒ ρair43π R3 dV

dt=ρblood g

43π R3−6πμblood RV− ρair

43π R3g

⇒ dVdt

=gρblood− ρair

ρair−

9μblood

2 ρairR2 VThe bubble will reach its maximum velocity when the acceleration is zero:

January 16, 2009 23


V max=29πgR2 ρblood−ρair

π μblood

We calculated for a bubble of 0.5mm in radius. All the bubble with smaller size will take more time to rise. After calculation in Maple, we found that the time and distance for that the bubble reach its maximum velocity are negligible. So we can assume that the velocity of the bubble is constant with the value V=Vmax=0.213m/s. As a result, the traveled distance is represented as below:

Figure 1. Distance traveled by the bubbled in function of time

If we assume that the velocity of liquid inside the tank is two times less than the velocity in the tubing. So the time needed for a fluid element pass through the tank is:

t=Distanceinput /output0.5×V fluid

With this time, the distance that a bubble raises is:

H=V max×t=V max×Distance

0.5×V fluid

So, in the case of the blood tank, the distance between input and output is ID=4.75 in, so H=2.5 in. In the case of the arterial tank, the distance is IDxcos45o, so H=3.0 in. In the two cases, the bubble gets far enough.

Maple code:

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> restart;> mju_blood:=0.0027:rho_blood:=1060:rho_air:=1.177:g:=9.81:> R:=0.5e-3:> eqn:=diff(V(t),t) = g*(rho_blood-rho_air)/rho_air -(6*mju_blood)/(rho_air*(4/3*R^2))*V(t);

eqn := ddt

V ( t ) = 8825.024325K 41291.41887 V ( t )

> V:=rhs(dsolve(eqn,V(0)=0,V(t)));

V := 45256535211750866

K 45256535211750866

e0K 4129141887

100000 t1

> V_max:=4/3*Pi*R^3*g*(rho_blood-rho_air)/(6*Pi*mju_blood*R);

V_max := 0.2137253834> t_max:=Re(solve(V=V_max,t));

t_max := 0.0005203217489The distance made from 0 to t_max> int(V,t=0..t_max);

0.0001060299410

The distance made from t_max> Distance:=int(V,t=0..t_max)+V_max*(t-t_max);

Distance :=K 0.0000051760243C 0.2137253834 t> plot(Distance,t=t_max..1,x=0..0.25, labels=["time(s)", "distance(m)"]);

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If we change the size of the bubble, we obtain:

- R=0.1mm

- R=1mm

January 16, 2009 26


Heat Transfer of TanksTank Dimensions: Ø = 4.875” x 5.5”

Tw = 98oF = 310.15K

Tw Tb Tb = 70oF (room temperature) = 294.26K

Attempt w/ LCM (Lumped Capacitance Method)

∙ use if Bi¿ is<0.1 Bi=h Lc /K

Lc=V / A=r /2=2.4375 /2=1.21875

K 302 Stainless=15.1w /mk table A .1

Volumeblood=1.9L=.0019m3

h=ρvCp

τ A s

T∞=98.2

r2 r1

Ti

Ti T∞

q” ln ¿¿¿1

2π r2hL

L=6.756 =.1714

K glycerin=.286 WmK

h=.1714m=6.75∈¿

K stainless=15.1 WmK

January 16, 2009 27


r1=.062m=2.4375∈¿

r1=.060m=2.375∈¿

RTot=ln¿¿¿

RTot=ln¿¿¿

RTot=.002 Kw

+52.37 Kw

=52.37 Kw

RTot=52.37 Kw

q=T ∞−T i

RTot=310.05 K−294.26 K

52.37 Kw

=.02w

w= JS

Bi=hLc

k=hh2oLc

k blood=hh2o ¿¿

h=ρvc p

τ A s

hh2o=2π KT L

2 π r2L ln ¿¿¿

Bi=7427.6 Wm2 K

¿¿

ξ=2.3455C1=1.5993α stainless=3.91×10−6m2/s

In order to find the approximate time for the blood in the tank to heat as well as the time it took for the water bath tank to heat to temperature the Lumped Capacitance method was used. We inputted these equations and values into excel and found that the time for the blood loop to heat would be less than 2 hours. These numbers indicate a show temperature rise that will be less likely to damage the blood.

January 16, 2009 28


Heat Loss in Tubes

T∞=¿70 ¿

Ti=98oF Tm=?

y

x |<-------------------L=50in------------->|

Blood Properties

70@µ=.00345Ns /m2

98@µ=.0027 Ns/m2

Ρ=1060 kg /m3

v=.789m /s

D=.5∈¿1.27×10−2m

Across=1.267×10−4m2

C pglycerin=2.49×103 J /kgK

310 K@Kglycerin=286×10−2W /mK

N uD=0.027R ed4 /5Pr1 /3 (μ/ μs )

0.14

Equations

Red=ev D / μ

h=NUD K /D

dTmdx

= PmC p

h (T s−Tm ) Pg. 498 equation 8.37

Properties and Equation from Fundamentals of Heat and Mass Transfer 6th editions

Solution

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dTmdx

= PhmC p

T s−PhmC p

T m

dTmdx

+ PhmC p

T s=PhmC p

Tm

C= PhmC p

Homogenous

T m1+ Ph

mC pTm=0

Assume solution: Tm=erx Tm1=ℜrx

r+ PhmC p

=0

r=−PhmCp

Particular Solution

Assume Solution: Tm=Ax+b ,T m1=A

A+ PhmC p

Ax+ PhmC p

b=CT s

PhmC p

Ax=0→ A=0

PhmC p

b=CT s→b=T s

Now: Tm=e( PhmCp

)x+T s

These calculations required the solution of a first order ordinary differential equation. The solution to this ODE led us to a find the final temperature of the tubes after a certain distance. The solution to this final equation was graphed in excel. The data shows that there is less than 1 degree change in temperature over 50 in of tubing. From this calculation it is clear that the heating system that we have

January 16, 2009 30


chosen will heat and maintain the blood at the appropriate temperature to model the human circulatory system.

January 16, 2009 31

Pfluid

Fmotor

Fmotor

OD


Linear motor’s force approximation

Abstract: this is an analysis to approximate the force needed by the linear motor.


Constants:- Fluid maximum pressure: Pfluid=2 psi- Outer diameter of the tubing: OD=11/16 in- Width of clamp: W=1 in

Assumption: The resistance of the tubing has been neglected

Analysis:

When the tubing is totally clamped, the length of clamp area is: L=Circumference

2=πOD

2=π 11

162

=1.1∈¿

So the force can be approximated as:Fmotor=P fluid× L×W=2 psi×1.1∈×1∈¿2.2 pounds

So if we neglect the resistance of the tubing, the force needed is 2.2 pounds.

January 16, 2009 32

h

hf

Pair

ID


Arterial tank dimensioning

Abstract: this is an analysis to dimension the arterial tank, and calculate its properties.


Constants from the physiological mocking system:-Compliance Cv=2.2 mL/mmHg=1.65e-8 m3/Pa-Fluid pressure at the output (absolute) Pf=860 mmHg =1.147e5 Pa-Density of glycerin ρ=1060km/m3

Constants from material constraints:

- Inner diameter of the tank ID=7.75 in=0.197 m-Height of the tank h=0.6 ft=0.183 m

Other constant: gravity g=9.81 m/s2

Assumption: ideal gas, small change in fluid height

Analysis:

From the equation: C v=

V air

Pair=V tank−A tank h f

Pf−ρg h f

We come up to the expression:h f=

C vP f−A tank hC v ρg−Atank

=0.121m=4.78∈¿

And:Pair=

V air

C v=1.13e5(absolute )

So we find that we need to fill in 4.78 inch-height liquid, and the pressure of the air in the tank must be 1.75psi to have a pressure of 100mmHg at the output of the tank.Reference:

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Yingjie Liu, Paul Allaire, Yi Wu, Houston Wood, Don Olsen. Construction of an artificial heart pump performance test system. Springer Science + Business Media. 11/30/2006

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Saline Flush

In search for a solution to flush out LVAD test loop post- blood testing, Drugs.com (a Drug

Information Online source) suggested the use of Sodium Chloride Irrigation, which is commonly

used in Clinical Pharmacology. 0.9% Sodium Chloride Irrigation USP is used for a variety of clinical

indications such as sterile irrigation of body cavities, tissues or wounds, indwelling urethral

catheters, surgical drainage tubes, and for washing, rinsing or soaking surgical dressings,

instruments and laboratory specimens. It also serves as a diluent or vehicle for drugs used for

irrigation or other pharmaceutical preparations. 0.9% Sodium Chloride Irrigation USP provides an

isotonic saline irrigation identical in composition with 0.9% Sodium Chloride Injection USP (normal

saline).1

Many vendors of biocompatible tubing or valves, which we will likely purchase materials,

such as Cole-Parmer.com, suggest sterilization by autoclave, radiation, or ethylene oxide. An

autoclave is a pressurized machine that heats aqueous solutions above their boiling point at normal

atmospheric pressure to make objects sterilized.2 Autoclaves can cost anywhere between $1,756

and $3,958, and are out of the price range of this project. 3 Radiation is also an option not suited for

this project, and would divert too much focus away from the scope. Ethylene oxide is the organic

compound with the formula C2H4O. This colorless flammable gas with a faintly sweet odor is the

simplest epoxide, a three-member ring consisting of two carbons and one oxygen atom, and is also

used for medical sterilization.4 This chemical is used in a chamber sterilization method, which a

chamber is flooded with a mixture of ethylene oxide and other gases that are later aerated. Because

of this, and the fact that it is toxic to inhale, we are choosing not to use ethylene oxide (nor radiation

or autoclave) to sterilize the LVAD test loop, but rather normal saline.

1Drugs.com. Sodium Chloride Irrigation. http://www.drugs.com/pro/sodium-chloride-irrigation.html2Wikipedia- Autoclave. http://en.wikipedia.org/wiki/Autoclave3 MedSupplier.com. http://www.medsupplier.com/autoclaves-and-sterilizers.aspx?gclid=CMiLl92otZgCFROgnAod4hT5bA4 Wikipedia- Ethylene Oxide. http://en.wikipedia.org/wiki/Ethylene_oxide

January 16, 2009 36


Sensor and DAQ analysisThis report looks at the resolution and sensitivity of the sensors and also the resolution of the DAQ. Besides is also looks at output voltage of then sensors so it is possible to compare DAQ and a sensor to figure out if they will be compatible with each other.

Sensitivity =

50m5

= 10mV/psi

If using accuracy of measurement for pressure is 0.1 in H20

Resolution = 10mV/psi× (0.1inches of water × 0.0361) psi = 36.1µV

Pressure Sensor (Omega PX26-005DV )

Specs Model's specsOutput format (@10V) 50mVPrice $36.00

Sensitivity=

1064

= 0.156V/liter

Resolution= 0.156V/liter× 0.05liter =7.8mV

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Flow sensor (Transducer+board digiflow-ext1 )

Specs Model's specsResolution 1ml/minOutput format -5V to 5VMax measurement ±32l /min

Frequency 15kHz to 18MHz (transmitter frequency)

Price Don’t need to purchase


Thermocouple. (Omega - KMQSS-020G-12)Specs Model's specsType UngroundedPrice $28.65

Resolution in volts =

full scale range2M

=

160m224

= 9.54nV/code

Thermocouple DAQ (NI 9211A)

Specs Model's specsResolution 24bitNumber input pins 4Voltage range -80mV to 80mV

Sampling rate 15 S/s (samples per secs)

Price $521

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Resolution in volts = 5−(−5)

2M =10222 = 2.384µV/code

Resolution in volts = 62m−(−62m)

2M =124m

222

= .2956nV/code

DAQ (OMB-DAQ-54)Specs Model's specsResolution 22 bits Number input pins 10 single endedVoltage range 31mV to 20VSampling rate 80 S/secPrice $649

Looking at the results for what was obtained from the calculations to figure out the sensitivity of the sensor and resolution of both the DAQ and sensor, it was found that if the PX2300 was purchased it can be coupled with the flow sensor and the USB 6009 DAQ. If instead the PX26 was purchased it is possible to couple it with the NI9211A DAQ and thermocouple. But if the OMB-DAQ-54 was bought it is possible to incorporate all the sensors including the flow sensor as it has a total of 10 single ended analog inputs.

Since the NI9211 has the a range of ±80mV along with the thermocouple, this makes it possible to use the PX26 pressure sensor, besides this it has a resolution of about 10nV/bit showing that it will be able to resolve the minute fluctuation of the sensors. The sensor is shown to output 10mV per psi of change. Assuming that required accuracy of the pressure reading is 0.1inches of water, it was found that the resolution of the sensor to be 36.1µV, meaning that the when the sensor detects 36.1µV then it indicates a change in pressure.

For the flow sensor, it has a sensitivity of about 0.156V/liter and a resolution of 7.8mV if it is assumed that the accuracy of the reading needs to be a 0.05 liter change. The output voltage range also corresponds of the OMB-DAQ-54 so they can be used together.

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LabVIEW Front Panel Prototype

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Controls:

LVAD Speed (rpm) Desired Flow ( L/m) Desired Pressure Decrease (mm Hg) PVS Speed (rpm) PVS upper/ lower (bpm) Resistance Valve control (in)

Indicators:

Real time/ Summary of pressure/ flow graphs PVS Change in Pressure and Flow with max/ min

indicators Temperatures in tank and at LVAD Boolean Warning lights if temperature is out of

range 2 Pressure Sensors 2 Flow Sensors

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