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Question: How to use numeric in dsolve?

Question:How to use numeric in dsolve?

Klockjj 10 Maple 17
ode dsolve numeric
February 04 2016
2

So im trying to solve multiple ODES using dsolve(numeric) but I jsut cant get it to work.

I kep getting this one error: 

Error, (in f) unable to store '-HFloat(0.020918994979034728)-HFloat(0.09184018333019917)*I' when datatype=float[8]

 

This is my uploaded file 

(for some reason the uploaded file didnt show the error at the bottom so i just pasted it in the spot it would appear.

Download CHE504_HW5.mw

> 

Given:
> 

restart
> 

dt := 2.07*0.254e-1

0.52578e-1

 (1)
> 

dto := 2.38*0.254e-1

0.60452e-1

 (2)
> 

ho := 5000

5000

 (3)
> 

``
> 

Ltube := 5

5

 (4)
> 

``
> 

Po := 2.5

2.5

 (5)
> 

To := 350

350

 (6)
> 

dp := 0.3e-2

0.3e-2

 (7)
> 

tau := 3

3

 (8)
> 

dpore := 5.2*10^(-9)

0.5200000000e-8

 (9)
> 

kfluid := 0.485e-1

0.485e-1

 (10)
> 

ksolid := 1.67

1.67

 (11)
> 

kpipe := 17

17

 (12)
> 

Cpair := 1.01

1.01

 (13)
> 

`μ_air` := 3.16*10^(-5)

0.3160000000e-4

 (14)
> 

rho := P(z)*(28.9*(1/1000))/(Rgas*(T(z)+273.15))

0.2890000000e-1*P(z)/(Rgas*(T(z)+273.15))

 (15)
> 

``
> 

Rgas := 8.2057*10^(-5)

0.8205700000e-4

 (16)
> 

``
> 

``
> 

density calculation n/v = (P/RT)*mw_air, kg/m^3
> 

``
> 

`ρi` := (2.5*28.966)/(0.82057e-1*(350+273.15))

1.416186012

 (17)
> 

NULL
> 

Volumetric flow, m^3/s
> 

((1/60)*((1/300)*((1/1000)*(180*1000000)*.4535)*(1/24))*(1/60))/(1.416)

0.2224085844e-2

 (18)
> 

``
> 

NULL
> 

Superficial velocity, m/s
> 

NULL
> 

Vsi := evalf(%/((1/4)*Pi*(2.07*0.254e-1)^2))

1.024362190

 (19)
> 

Gs constant, kg/m^2-s

Error, missing operator or `;`

  
> 

Gsi := `ρi`*Vsi

1.450687405

 (20)
> 

Gs := 1.45

1.45

 (21)
> 

``
> 

``
> 

NULL
> 

Void fraction, epsilon,b
> 

`εb` := .38+0.73e-1*(1+(0.525e-1/(0.3e-2)-2)^2/(0.525e-1/(0.3e-2))^2)

.5102677551

 (22)
> 

hi
> 

hi := 3.6*kfluid*(dp*Gs/(`μ_air`*`εb`))^.365/dp

448.9928888

 (23)
> 

kinetic parameter
> 

K := ln(19.837-13636/(T(z)+273.15))

ln(19.837-13636/(T(z)+273.15))

 (24)
> 

radial disperssion Coeff
> 

Dr := Vs*dp/(9*(1+19.4*(dp/dt)^2))

0.3135309899e-3*Vs

 (25)
> 

thermal conductivity calculations
> 

Kbs := kfluid*(`εb`+(1-`εb`)/(2/3*(1+kfluid/ksolid)))

0.5937050269e-1

 (26)
> 

``
> 

Kbd := `εb`*Cpair*Gs*dp/(9*(1+19.4*(dp/dt)^2))

0.2342976727e-3

 (27)
> 

KB := Kbs+Kbd

0.5960480036e-1

 (28)
> 

Heat of reaction (deltaH), Find heat of formation for each reactant and product--> dHrxn = heat of formation(product)-heat of formation(reactant)

Error, missing operator or `;`

  
> 

heat of formation = A + B*T + C*T^2
> 

Hfacrolein := -7.076*10+(-5.59*10^(-2))*(273.15+350)+3.86*10^(-5)*(273.15+350)^2

-90.60509039

 (29)
> 

Hfwater := -238.41-0.122e-1*(350+273.15)+2.76*10^(-6)*(273.15+350)^2

-244.9406781

 (30)
> 

Hfpropylene := 3.62*10+(-6.49*10^(-2))*(273.15+350)+3.049*10^(-5)*(273.15+350)^2

7.59731748

 (31)
> 

`ΔHrxn` := Hfacrolein-Hfwater-Hfpropylene

146.7382702

 (32)
> 

Solving nodified Ergun Equation
> 

f := (1-`εb`)*(1.75+(150*(1-`εb`))*`μ_air`/(dp*Gs))/`εb`

2.191735176

 (33)
> 

``
> 

Determining U of the wall and Ueffective
> 

``
> 

``
> 

Uwall := 1/(1/hi+ln(dto/dt)/(2*ksolid)+1/ho)

22.61972270

 (34)
> 

``
> 

Ueff := 1/(1/Uwall+(1/2)*dt/(4*KB))

6.473624190

 (35)
> 

ode1 := Gs*(diff(Cprop(z), z))/rho = -K*Cprop(z)

0.4117046714e-2*(T(z)+273.15)*(diff(Cprop(z), z))/P(z) = -ln(19.837-13636/(T(z)+273.15))*Cprop(z)

 (36)
> 

ode2 := Gs*Cpair*(diff(T(z), z)) = -K*Cprop(z)*`ΔHrxn`-4*Ueff*(T(z)-350)/dt

1.4645*(diff(T(z), z)) = -146.7382702*ln(19.837-13636/(T(z)+273.15))*Cprop(z)-492.4968000*T(z)+172373.8800

 (37)
> 

ode3 := diff(P(z), z) = -f*Gs^2/(rho*dp)

diff(P(z), z) = -4.361346783*(T(z)+273.15)/P(z)

 (38)
> 

Ics1 := Cprop(0) = 0.3e-1

Cprop(0) = 0.3e-1

 (39)
> 

Ics2 := T(0) = 350

T(0) = 350

 (40)
> 

Ics3 := P(0) = 2.5

P(0) = 2.5

 (41)
> 

NULL
> 

dsolve({Ics1, Ics2, Ics3, ode1, ode2, ode3}, {Cprop(z), P(z), T(z)})

Error, (in f) unable to store '-HFloat(0.020918994979034728)-HFloat(0.09184018333019917)*I' when datatype=float[8]

 

  
> 

NULL
> 

NULL
> 

``
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