Hi, I'm plotting a graph which involve differencial equation at which i'm using ODE15s to solve it.
But no matter how I check, i couldn't find any errors.
Can someone help me?
Here is my code
The main files
alpha = 1000; % Solution density correlation parameter (kg/m^3)
beta = 1100; % Solution density correlation parameter (kg/m^3)H1 = 3; % Total tank height (m)
H2 = 2; % Height of top zone of tank (m)
L = 3; % Tank width (and length) (m)
CV = 0.256; % Outlet valve coefficient ((m^3/s)/(kPa/(kg/m^3))^0.5)
deltaP = 300; % Pressure drop over control valve (kPa)
Bc = 0.5; % Controller bias (-);
Kc = -5; % Controller gain (-)
taus = 10; % Level sensor time constant (s)
Ga = 1; % Actuator gain (-)
taua = 20; % Actuator time constant (s)
xia = 0.8; % Actuator damping factor (-)
tf = 2400; % Final simulation time (s)
MW0 = 16750; % Initial mass of water in tank (kg)
MB0 = 7150; % Initial mass of boganite in tank (kg)
hs0 = 2.5; % Initial level sensor reading (m)
w0 = 0; % Initial scaled valve stem velocity (1/s)
S0 = 0.5; % Initial dimensionless valve position (-)
%
% Pack the Parameters into single Pack
p = {alpha, beta, H1, H2, L, CV, deltaP, Bc, Kc, taus, Ga, taua, xia}; % Pack up the initial conditions
y0 = [MW0 MB0 hs0 w0 S0]; tspan = [0 tf]; [t,y] = ode15s(@(t,y) mass(t,y,p), tspan, y0);and another files
mass.m which is my function files
function dmdt=mass(t,y,p)% Function of dM/dt, solving change of total mass over changing
% time
% Unpacking the initial condition to local state variable m from
% bogvars.m
MW = y(1);MB = y(2);hs = y(3);w = y(4);S = y(5);% Unpacking the parameters from bogvars.m
[alpha, beta, H1, H2, L, CV, deltaP, Bc, Kc, taus, Ga, taua, xia]=p{:};% Retriving all the current value at time t using the function given
[QLi,CBLi,mdotBSi,hSP] = bogctrl(t);% Algebraic equations
Mt = MW + MB; % eqn (14)
xBLo = MB/Mt; % eqn (11)
rhoLo = alpha + beta*(xBLo); % eqn (10)
hSPp = hSP/H1; % eqn (21)
htp = hs/H1; % eqn (20)
Vbot = 0.5*(H1+H2)*L^2; % eqn (16)
VT = Mt/rhoLo; % eqn (15)
mdotBLi = QLi*CBLi; % eqn (3)
sigma = hSPp - htp; % eqn (22)
Vtop = VT - Vbot; % eqn (17)
QLo = CV*S*(deltaP/rhoLo)^(0.5); % eqn (26)
mdotLo = rhoLo*QLo; % eqn (13)
xWLo = 1 - xBLo; % eqn (12)
syms mdotLi rhoLi xBLi positiveeq1 = (rhoLi*QLi)==mdotLi; eq2 = alpha + beta*xBLi==rhoLi;eq3 = xBLi*mdotLi==mdotBLi; sol=solve(eq1,eq2,eq3,mdotLi,rhoLi,xBLi);sol.mdotLisol.rhoLisol.xBLidouble(sol.mdotLi)double(sol.rhoLi)double(sol.xBLi)Oc = Bc + Kc*sigma; % eqn (23)
h = H1-H2+(Vtop/L^2); % eqn (18)
mdotBLo = xBLo*mdotLo; % eqn (9)
mdotWLo = xWLo*mdotLo; % eqn (8)
mdotWLi = mdotLi - mdotBLi; % eqn (7)
% Evaluate the derivative of dMw/dt
dMWdt = mdotWLi-mdotWLo; % eqn (1)
dMBdt = mdotBLi + mdotBSi - mdotBLo; % eqn (2)
dhsdt = (h-hs)/taus; % eqn (19)
dwdt = ((Ga*Oc-S)/taua^2)-(2*(xia/taua)*w); % eqn (24)
dSdt = w; % eqn (25)
dmdt = [dMWdt dMBdt dhsdt dwdt dSdt]';endthe errors are here
Error using odearguments (line 110)Inputs must be floats, namely single or double.Error in ode15s (line 148)[neq, tspan, ntspan, next, t0, tfinal, tdir, y0, f0, odeArgs, odeFcn, ...Error in bogvars (line 34)[t,y] = ode15s(@(t,y) mass(t,y,p), tspan, y0);And the file which calculate the flow,
function [QLi,CBLi,mdotBSi,hSP] = bogctrl(t)% BOGCTRL: Dynamic inlet conditions and level setpoint for solubilisation
% tank model
%% Input variable:
% t Current time (s)
% Output variables:
% QLi Inlet liquor volumetric flowrate (m^3/s)
% CBLi Inlet boganite concentration in liquor (kg/m^3)
% mdotBSi Inlet mass flowrate of solid boganite (kg/s)
% hSP Level control set-point (m)
% Inlet liquor conditions remain fixed for the duration of the simulation
QLi = 0.0565;CBLi = 43;% Introduce step change in level set-point at t = 5 minutes
if t < 300 hSP = 2.5;else hSP = 2.2;end% Introduce step change in solids stream feed rate at t = 20 minutes
if t < 1200 mdotBSi = 21.5;else mdotBSi = 21.5*0.7;endAppreciate any help 🙂
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