272 lines
11 KiB
C#
272 lines
11 KiB
C#
using FluidSim.Components;
|
||
using FluidSim.Core;
|
||
using FluidSim.Interfaces;
|
||
using SFML.Graphics;
|
||
using SFML.System;
|
||
using System;
|
||
|
||
namespace FluidSim.Tests
|
||
{
|
||
public class SingleCylScenario : Scenario
|
||
{
|
||
// ---------- Engine components ----------
|
||
private Crankshaft crankshaft;
|
||
private Cylinder cylinder;
|
||
|
||
// ---------- Fluid network ----------
|
||
private PipeSystem pipeSystem;
|
||
private BoundarySystem boundaries;
|
||
private Solver solver;
|
||
|
||
// Volumes
|
||
private Volume0D intakePlenum;
|
||
|
||
// Ports
|
||
private Port plenumInlet, plenumOutlet;
|
||
|
||
// Orifice / open‑end indices
|
||
private int throttleAreaIdx, plenumRunnerIdx, intakeValveIdx, exhaustValveIdx;
|
||
private int intakeOpenIdx, exhaustOpenIdx;
|
||
private float[] orificeAreas;
|
||
|
||
// Sound
|
||
private SoundProcessor exhaustSound, intakeSound;
|
||
private OutdoorExhaustReverb reverb;
|
||
|
||
// ---------- Simulation state ----------
|
||
private double dt;
|
||
private int stepCount;
|
||
|
||
// ---------- Geometry (Lifan YX140) ----------
|
||
// Bore 56 mm, Stroke 57 mm, CR 9.5
|
||
private const float Bore = 0.056f;
|
||
private const float Stroke = 0.057f;
|
||
private const float ConRod = 0.110f; // typical for 57 mm stroke
|
||
private const float CompressionRatio = 9.5f;
|
||
|
||
// Valve diameters (intake 27 mm, exhaust 23 mm)
|
||
private const float IntakeValveDiam = 0.027f;
|
||
private const float ExhaustValveDiam = 0.023f;
|
||
private const float ValveLift = 0.006f; // 6 mm peak lift
|
||
|
||
// Valve timings (degrees, 720° four‑stroke)
|
||
// Intake: 15° BTDC → 45° ABDC
|
||
private const float IVO = 345f; // 15° BTDC
|
||
private const float IVC = 585f; // 45° ABDC (180°+45°)
|
||
// Exhaust: 45° BBDC → 15° ATDC
|
||
private const float EVO = 135f; // 45° BBDC (180°-45°)
|
||
private const float EVC = 375f; // 15° ATDC (360°+15°)
|
||
|
||
// Spark advance: 30° BTDC
|
||
private const float SparkAdv = 30f;
|
||
|
||
// Pipe / plenum sizes
|
||
private const float PipeDiam = 0.025f; // 25 mm intake / exhaust
|
||
private const float PipeArea = 0.00049087f; // π*D²/4
|
||
private const float PlenumVolume = 0.0005f; // 500 mL
|
||
private const float MaxThrottleArea = 1e-4f; // ~1 cm² (fully open)
|
||
|
||
// Pipe lengths and cell counts
|
||
private const float IntakeLenBefore = 0.15f; // 15 cm before throttle
|
||
private const float RunnerLen = 0.25f; // 25 cm runner
|
||
private const float ExhaustLen = 0.60f; // 60 cm exhaust
|
||
private const int CellsBefore = 6;
|
||
private const int CellsRunner = 10;
|
||
private const int CellsExhaust = 24;
|
||
|
||
public override void Initialize(int sampleRate)
|
||
{
|
||
dt = 1.0 / sampleRate;
|
||
|
||
// ---------- Crankshaft ----------
|
||
crankshaft = new Crankshaft(600); // start at ~600 RPM
|
||
crankshaft.Inertia = 0.2f;
|
||
crankshaft.FrictionConstant = 2.0f;
|
||
crankshaft.FrictionViscous = 0.04f;
|
||
|
||
// ---------- Cylinder ----------
|
||
cylinder = new Cylinder(Bore, Stroke, ConRod, CompressionRatio,
|
||
IVO, IVC, EVO, EVC, crankshaft)
|
||
{
|
||
IntakeValveDiameter = IntakeValveDiam,
|
||
ExhaustValveDiameter = ExhaustValveDiam,
|
||
IntakeValveLift = ValveLift,
|
||
ExhaustValveLift = ValveLift,
|
||
SparkAdvance = SparkAdv,
|
||
EnergyVariationFraction = 0.03f, // small cycle‑to‑cycle variation
|
||
MisfireProbability = 0.0f
|
||
};
|
||
|
||
// ---------- Pipe system ----------
|
||
int totalCells = CellsBefore + CellsRunner + CellsExhaust;
|
||
int[] pipeStart = { 0, CellsBefore, CellsBefore + CellsRunner };
|
||
int[] pipeEnd = { CellsBefore, CellsBefore + CellsRunner, totalCells };
|
||
|
||
float[] areas = new float[totalCells];
|
||
float[] dxs = new float[totalCells];
|
||
float dxBefore = IntakeLenBefore / CellsBefore;
|
||
float dxRunner = RunnerLen / CellsRunner;
|
||
float dxExh = ExhaustLen / CellsExhaust;
|
||
|
||
for (int i = 0; i < totalCells; i++)
|
||
{
|
||
areas[i] = PipeArea;
|
||
if (i < CellsBefore)
|
||
dxs[i] = dxBefore;
|
||
else if (i < CellsBefore + CellsRunner)
|
||
dxs[i] = dxRunner;
|
||
else
|
||
dxs[i] = dxExh;
|
||
}
|
||
|
||
float rho0 = 101325f / (287f * 300f);
|
||
pipeSystem = new PipeSystem(totalCells, pipeStart, pipeEnd, areas, dxs,
|
||
rho0, 0f, 101325f);
|
||
pipeSystem.DampingMultiplier = 0.5f;
|
||
pipeSystem.EnergyRelaxationRate = 0f; // adiabatic pipes
|
||
pipeSystem.AmbientPressure = 101325f;
|
||
|
||
// ---------- Volumes ----------
|
||
intakePlenum = new Volume0D(PlenumVolume, 101325f, 300f);
|
||
plenumInlet = intakePlenum.CreatePort();
|
||
plenumOutlet = intakePlenum.CreatePort();
|
||
|
||
// ---------- Boundary system ----------
|
||
boundaries = new BoundarySystem(pipeSystem, maxOrifices: 4, maxOpenEnds: 2);
|
||
|
||
throttleAreaIdx = 0;
|
||
plenumRunnerIdx = 1;
|
||
intakeValveIdx = 2;
|
||
exhaustValveIdx = 3;
|
||
|
||
// Open ends
|
||
boundaries.AddOpenEnd(pipeIndex: 0, isLeftEnd: true, 101325f, PipeArea);
|
||
intakeOpenIdx = 0;
|
||
boundaries.AddOpenEnd(pipeIndex: 2, isLeftEnd: false, 101325f, PipeArea);
|
||
exhaustOpenIdx = 1;
|
||
|
||
// Orifices
|
||
// throttle – variable area, low discharge for restriction
|
||
boundaries.AddOrifice(plenumInlet, pipeIndex: 0, isLeftEnd: false,
|
||
throttleAreaIdx, dischargeCoeff: 0.8f);
|
||
// plenum → runner
|
||
boundaries.AddOrifice(plenumOutlet, pipeIndex: 1, isLeftEnd: true,
|
||
plenumRunnerIdx, dischargeCoeff: 1.0f);
|
||
// intake valve
|
||
boundaries.AddOrifice(cylinder.IntakePort, pipeIndex: 1, isLeftEnd: false,
|
||
intakeValveIdx, dischargeCoeff: 1.0f);
|
||
// exhaust valve
|
||
boundaries.AddOrifice(cylinder.ExhaustPort, pipeIndex: 2, isLeftEnd: true,
|
||
exhaustValveIdx, dischargeCoeff: 1.0f);
|
||
|
||
orificeAreas = new float[4];
|
||
orificeAreas[plenumRunnerIdx] = PipeArea; // fixed full‑bore
|
||
|
||
// ---------- Solver ----------
|
||
solver = new Solver { SubStepCount = 5, EnableProfiling = false };
|
||
solver.SetTimeStep(dt);
|
||
solver.SetPipeSystem(pipeSystem);
|
||
solver.SetBoundarySystem(boundaries);
|
||
solver.AddComponent(cylinder);
|
||
solver.AddComponent(intakePlenum);
|
||
|
||
// ---------- Sound ----------
|
||
exhaustSound = new SoundProcessor(sampleRate, 1f) { Gain = 0.2f };
|
||
intakeSound = new SoundProcessor(sampleRate, 1f) { Gain = 0.2f };
|
||
reverb = new OutdoorExhaustReverb(sampleRate);
|
||
|
||
stepCount = 0;
|
||
Console.WriteLine("Single‑cylinder engine (YX140) ready.");
|
||
}
|
||
|
||
public override float Process()
|
||
{
|
||
// ---- Crank and cylinder pre‑step ----
|
||
crankshaft.Step((float)dt);
|
||
cylinder.PreStep((float)dt);
|
||
|
||
// ---- Update variable areas ----
|
||
float throttledArea = MaxThrottleArea * Math.Clamp(Throttle, 0.0001f, 1.0f);
|
||
orificeAreas[throttleAreaIdx] = throttledArea;
|
||
orificeAreas[intakeValveIdx] = cylinder.IntakeValveArea;
|
||
orificeAreas[exhaustValveIdx] = cylinder.ExhaustValveArea;
|
||
boundaries.SetOrificeAreas(orificeAreas);
|
||
|
||
// ---- Fluids step ----
|
||
solver.Step();
|
||
stepCount++;
|
||
|
||
// ---- Sound ----
|
||
float exhaustFlow = boundaries.GetOpenEndMassFlow(exhaustOpenIdx);
|
||
float intakeFlow = boundaries.GetOpenEndMassFlow(intakeOpenIdx);
|
||
|
||
float exhaustDry = exhaustSound.Process(exhaustFlow);
|
||
float intakeDry = intakeSound.Process(intakeFlow);
|
||
|
||
if (stepCount % 2000 == 0)
|
||
{
|
||
float rpm = crankshaft.AngularVelocity * 60f / (2f * MathF.PI);
|
||
Console.WriteLine($"Step {stepCount}, RPM={rpm:F0}, CylP={cylinder.Pressure / 1e5f:F2} bar, " +
|
||
$"Throttle={Throttle * 100:F0}%");
|
||
}
|
||
|
||
return reverb.Process(exhaustDry + intakeDry);
|
||
}
|
||
|
||
public override void Draw(RenderWindow target)
|
||
{
|
||
float winW = target.GetView().Size.X;
|
||
float winH = target.GetView().Size.Y;
|
||
|
||
float intakeY = winH / 2f - 40f;
|
||
float exhaustY = winH / 2f + 80f;
|
||
float leftX = 40f;
|
||
|
||
// Intake open end marker
|
||
var om = new CircleShape(5f) { FillColor = Color.Cyan };
|
||
om.Position = new Vector2f(leftX - 5f, intakeY - 5f);
|
||
target.Draw(om);
|
||
|
||
// Pipe 0 – before throttle
|
||
float p0EndX = leftX + 80f;
|
||
DrawPipe(target, pipeSystem, 0, intakeY, leftX, p0EndX);
|
||
|
||
// Throttle symbol
|
||
float thrX = p0EndX + 5f;
|
||
var thr = new RectangleShape(new Vector2f(8f, 30f))
|
||
{
|
||
FillColor = Color.Yellow,
|
||
Position = new Vector2f(thrX, intakeY - 15f)
|
||
};
|
||
target.Draw(thr);
|
||
|
||
// Plenum volume
|
||
float plenW = 60f, plenH = 50f;
|
||
float plenLeftX = thrX + 12f;
|
||
float plenCenterX = plenLeftX + plenW / 2f;
|
||
float plenTopY = intakeY - plenH / 2f;
|
||
DrawVolume(target, intakePlenum, plenCenterX, plenTopY, plenW, plenH);
|
||
|
||
// Pipe 1 – runner
|
||
float rStartX = plenLeftX + plenW + 10f;
|
||
float rEndX = rStartX + 100f;
|
||
DrawPipe(target, pipeSystem, 1, intakeY, rStartX, rEndX);
|
||
|
||
// Cylinder
|
||
float cylCX = rEndX + 50f;
|
||
float cylTopY = intakeY - 120f;
|
||
float cylW = 80f, cylMaxH = 240f;
|
||
DrawCylinder(target, cylinder, cylCX, cylTopY, cylW, cylMaxH);
|
||
|
||
// Pipe 2 – exhaust
|
||
float exhStartX = cylCX + cylW / 2f + 20f;
|
||
float exhEndX = winW - 60f;
|
||
DrawPipe(target, pipeSystem, 2, exhaustY, exhStartX, exhEndX);
|
||
|
||
// Exhaust open end
|
||
var em = new CircleShape(5f) { FillColor = Color.Magenta };
|
||
em.Position = new Vector2f(exhEndX - 5f, exhaustY - 5f);
|
||
target.Draw(em);
|
||
}
|
||
}
|
||
} |