Files
reactor/src/reactor_class.js

319 lines
12 KiB
JavaScript

const ASM3 = require('./asm3_class.js');
const { create, all } = require('mathjs');
const config = {
matrix: 'Array' // use Array as the matrix type
};
const math = create(all, config);
const OXYGEN_INDEX = 0;
const NUM_SPECIES = 13;
/**
* Assert that no NaN values are present in an array.
* @param {Array} arr
* @param {string} label
*/
function assertNoNaN(arr, label = "array") {
if (Array.isArray(arr)) {
for (const el of arr) {
assertNoNaN(el, label);
}
} else {
if (Number.isNaN(arr)) {
throw new Error(`NaN detected in ${label}!`);
}
}
}
class Reactor {
/**
* Reactor base class.
* @param {object} config - Configuration object containing reactor parameters.
*/
constructor(config) {
this.asm = new ASM3();
this.Vl = config.volume; // fluid volume reactor [m3]
this.Fs = Array(config.n_inlets).fill(0.0); // fluid debits per inlet [m3 d-1]
this.Cs_in = Array.from(Array(config.n_inlets), () => new Array(NUM_SPECIES).fill(0.0)); // composition influents
this.OTR = 0.0; // oxygen transfer rate [g O2 d-1]
this.kla = config.kla; // if NaN, use externaly provided OTR [d-1]
this.currentTime = Date.now(); // milliseconds since epoch [ms]
this.timeStep = 1 / (24 * 60 * 15); // time step [d]
this.speedUpFactor = 60; // speed up factor for simulation, 60 means 1 minute per simulated second
}
/**
* Setter for influent data.
* @param {object} input - Input object (msg) containing payload with inlet index, flow rate, and concentrations.
*/
set setInfluent(input) {
let index_in = input.payload.inlet;
this.Fs[index_in] = input.payload.F;
this.Cs_in[index_in] = input.payload.C;
// DEBUG
// console.log("Pe total " + this.length*math.sum(this.Fs)/(this.D*this.A));
// console.log("Pe local " + this.d_x*math.sum(this.Fs)/(this.D*this.A));
// console.log("Co ad " + math.sum(this.Fs)*this.timeStep/(this.A*this.d_x));
// console.log("Co D " + this.D*this.timeStep/(this.d_x*this.d_x));
}
/**
* Setter for OTR (Oxygen Transfer Rate).
* @param {object} input - Input object (msg) containing payload with OTR value [g O2 d-1].
*/
set setOTR(input) {
this.OTR = input.payload;
}
/**
*
* @param {number} S_O - Dissolved oxygen concentration [g O2 m-3].
* @param {number} T - Temperature in Celsius, default to 20 C.
* @returns
*/
_calcOTR(S_O, T = 20.0) { // caculate the OTR using basic correlation, default to temperature: 20 C
let S_O_sat = 14.652 - 4.1022e-1 * T + 7.9910e-3 * T * T + 7.7774e-5 * T * T * T;
return this.kla * (S_O_sat - S_O);
}
/**
* Clip values in an array to zero.
* @param {Array} arr - Array of values to clip.
* @returns {Array} - New array with values clipped to zero.
*/
_arrayClip2Zero(arr) {
if (Array.isArray(arr)) {
return arr.map(x => this._arrayClip2Zero(x));
} else {
return arr < 0 ? 0 : arr;
}
}
/**
* Update the reactor state based on the new time.
* @param {number} newTime - New time to update reactor state to, in milliseconds since epoch.
*/
updateState(newTime) { // expect update with timestamp
const day2ms = 1000 * 60 * 60 * 24;
let n_iter = Math.floor(this.speedUpFactor * (newTime - this.currentTime) / (this.timeStep * day2ms));
if (n_iter) {
let n = 0;
while (n < n_iter) {
this.tick(this.timeStep);
n += 1;
}
this.currentTime += n_iter * this.timeStep * day2ms / this.speedUpFactor;
}
}
}
class Reactor_CSTR extends Reactor {
/**
* Reactor_CSTR class for Continuous Stirred Tank Reactor.
* @param {object} config - Configuration object containing reactor parameters.
*/
constructor(config) {
super(config);
this.state = config.initialState;
}
/**
* Getter for effluent data.
* @returns {object} Effluent data object (msg), defaults to inlet 0.
*/
get getEffluent() { // getter for Effluent, defaults to inlet 0
return { topic: "Fluent", payload: { inlet: 0, F: math.sum(this.Fs), C: this.state }, timestamp: this.currentTime };
}
/**
* Tick the reactor state using the forward Euler method.
* @param {number} time_step - Time step for the simulation [d].
* @returns {Array} - New reactor state.
*/
tick(time_step) { // tick reactor state using forward Euler method
const inflow = math.multiply(math.divide([this.Fs], this.Vl), this.Cs_in)[0];
const outflow = math.multiply(-1 * math.sum(this.Fs) / this.Vl, this.state);
const reaction = this.asm.compute_dC(this.state);
const transfer = Array(NUM_SPECIES).fill(0.0);
transfer[OXYGEN_INDEX] = isNaN(this.kla) ? this.OTR : this._calcOTR(this.state[OXYGEN_INDEX]); // calculate OTR if kla is not NaN, otherwise use externaly calculated OTR
const dC_total = math.multiply(math.add(inflow, outflow, reaction, transfer), time_step);
assertNoNaN(dC_total, "change in state");
this.state = this._arrayClip2Zero(math.add(this.state, dC_total)); // clip value element-wise to avoid negative concentrations
assertNoNaN(this.state, "new state");
return this.state;
}
}
class Reactor_PFR extends Reactor {
/**
* Reactor_PFR class for Plug Flow Reactor.
* @param {object} config - Configuration object containing reactor parameters.
*/
constructor(config) {
super(config);
this.length = config.length; // reactor length [m]
this.n_x = config.resolution_L; // number of slices
this.d_x = this.length / this.n_x;
this.A = this.Vl / this.length; // crosssectional area [m2]
this.state = Array.from(Array(this.n_x), () => config.initialState.slice())
// console.log("Initial State: ")
// console.log(this.state)
this.D = 0.0; // axial dispersion [m2 d-1]
this.D_op = this._makeDoperator(true, true);
assertNoNaN(this.D_op, "Derivative operator");
this.D2_op = this._makeD2operator();
assertNoNaN(this.D2_op, "Second derivative operator");
}
/**
* Setter for axial dispersion.
* @param {object} input - Input object (msg) containing payload with dispersion value [m2 d-1].
*/
set setDispersion(input) {
this.D = input.payload;
}
/**
* Getter for effluent data.
* @returns {object} Effluent data object (msg), defaults to inlet 0.
*/
get getEffluent() {
return { topic: "Fluent", payload: { inlet: 0, F: math.sum(this.Fs), C: this.state.at(-1) }, timestamp: this.currentTime };
}
_applyBoundaryConditions(state) {
// apply boundary conditions
if (math.sum(this.Fs) > 0) { // Danckwerts BC
const BC_C_in = math.multiply(1 / math.sum(this.Fs), [this.Fs], this.Cs_in)[0];
const BC_gradient = Array(this.n_x).fill(0.0);
BC_gradient[0] = -1;
BC_gradient[1] = 1;
let Pe = this.length * math.sum(this.Fs) / (this.D * this.A)
const BC_dispersion = math.multiply((1 - (1 + 4 * this.volume / math.sum(this.Fs) / Pe) ^ 0.5) / Pe, [BC_gradient], state)[0];
state[0] = math.add(BC_C_in, BC_dispersion).map(val => val < 0 ? 0 : val);
} else { // Neumann BC (no flux)
state[0] = state[1];
}
// Neumann BC (no flux)
state[this.n_x - 1] = state[this.n_x - 2]
}
/**
* Tick the reactor state using explicit finite difference method.
* @param {number} time_step - Time step for the simulation [d].
* @returns {Array} - New reactor state.
*/
tick(time_step) {
const dispersion = math.multiply(this.D / (this.d_x * this.d_x), this.D2_op, this.state);
const advection = math.multiply(-1 * math.sum(this.Fs) / (this.A * this.d_x), this.D_op, this.state);
const reaction = this.state.map((state_slice) => this.asm.compute_dC(state_slice));
const transfer = Array.from(Array(this.n_x), () => new Array(NUM_SPECIES).fill(0.0));
assertNoNaN(dispersion, "dispersion");
assertNoNaN(advection, "advection");
assertNoNaN(reaction, "reaction");
if (isNaN(this.kla)) { // calculate OTR if kla is not NaN, otherwise use externally calculated OTR
transfer.forEach((x) => { x[OXYGEN_INDEX] = this.OTR; });
} else {
transfer.forEach((x, i) => { x[OXYGEN_INDEX] = this._calcOTR(this.state[i][OXYGEN_INDEX]); });
}
const dC_total = math.multiply(math.add(dispersion, advection, reaction, transfer), time_step);
assertNoNaN(dC_total, "change in state");
const stateNew = math.add(this.state, dC_total);
assertNoNaN(stateNew, "new state");
this._applyBoundaryConditions(stateNew);
assertNoNaN(stateNew, "new state post BC");
this.state = this._arrayClip2Zero(stateNew);
return stateNew;
}
/**
* Create finite difference first derivative operator.
* @param {boolean} central - Use central difference scheme if true, otherwise use upwind scheme.
* @param {boolean} higher_order - Use higher order scheme if true, otherwise use first order scheme.
* @returns {Array} - First derivative operator matrix.
*/
_makeDoperator(central = false, higher_order = false) { // create gradient operator
if (higher_order) {
if (central) {
const I = math.resize(math.diag(Array(this.n_x).fill(1/12), -2), [this.n_x, this.n_x]);
const A = math.resize(math.diag(Array(this.n_x).fill(-2/3), -1), [this.n_x, this.n_x]);
const B = math.resize(math.diag(Array(this.n_x).fill(2/3), 1), [this.n_x, this.n_x]);
const C = math.resize(math.diag(Array(this.n_x).fill(-1/12), 2), [this.n_x, this.n_x]);
const D = math.add(I, A, B, C);
const NearBoundary = Array(this.n_x).fill(0.0);
NearBoundary[0] = -1/4;
NearBoundary[1] = -5/6;
NearBoundary[2] = 3/2;
NearBoundary[3] = -1/2;
NearBoundary[4] = 1/12;
D[1] = NearBoundary;
NearBoundary.reverse();
D[this.n_x-2] = math.multiply(-1, NearBoundary);
D[0] = Array(this.n_x).fill(0); // set by BCs elsewhere
D[this.n_x-1] = Array(this.n_x).fill(0);
return D;
} else {
throw new Error("Upwind higher order method not implemented! Use central scheme instead.");
}
} else {
const I = math.resize(math.diag(Array(this.n_x).fill(1 / (1 + central)), central), [this.n_x, this.n_x]);
const A = math.resize(math.diag(Array(this.n_x).fill(-1 / (1 + central)), -1), [this.n_x, this.n_x]);
const D = math.add(I, A);
D[0] = Array(this.n_x).fill(0); // set by BCs elsewhere
D[this.n_x - 1] = Array(this.n_x).fill(0);
return D;
}
}
/**
* Create central finite difference second derivative operator.
* @returns {Array} - Second derivative operator matrix.
*/
_makeD2operator() { // create the central second derivative operator
const I = math.diag(Array(this.n_x).fill(-2), 0);
const A = math.resize(math.diag(Array(this.n_x).fill(1), 1), [this.n_x, this.n_x]);
const B = math.resize(math.diag(Array(this.n_x).fill(1), -1), [this.n_x, this.n_x]);
const D2 = math.add(I, A, B);
D2[0] = Array(this.n_x).fill(0); // set by BCs elsewhere
D2[this.n_x - 1] = Array(this.n_x).fill(0);
return D2;
}
}
module.exports = { Reactor_CSTR, Reactor_PFR };
// DEBUG
// state: S_O, S_I, S_S, S_NH, S_N2, S_NO, S_HCO, X_I, X_S, X_H, X_STO, X_A, X_TS
// let initial_state = [0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1];
// const Reactor = new Reactor_PFR(200, 10, 10, 1, 100, initial_state);
// Reactor.Cs_in[0] = [0.0, 30., 100., 16., 0., 0., 5., 25., 75., 30., 0., 0., 125.];
// Reactor.Fs[0] = 10;
// Reactor.D = 0.01;
// let N = 0;
// while (N < 5000) {
// console.log(Reactor.tick(0.001));
// N += 1;
// }