sepehr
5bd180b5b8
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Capture uncommitted solver robustness work (regularization, domain errors, linear solver lifecycle, tube DP/MSH), web workbench updates, and synced BMAD skills across IDE agent folders before starting BPHX pressure-drop. Co-authored-by: Cursor <cursoragent@cursor.com>
67 lines
2.4 KiB
Rust
67 lines
2.4 KiB
Rust
//! Quick empirical check of MSH smoothness near x=1.
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//!
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//! Run with: cargo test --release -p entropyk-components --lib -- test_msh_smoothness_empirical real_check --nocapture
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use entropyk_components::heat_exchanger::two_phase_dp::{
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friedel_gradient, msh_gradient, FriedelInput,
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};
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#[test]
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fn real_check() {
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// R134a-like at 5 °C, mass flux typical of DX evaporator at opening=1.
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let base = FriedelInput {
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mass_flux: 300.0,
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diameter: 0.0095,
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quality: 0.5,
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rho_liquid: 1290.0,
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rho_vapor: 17.4,
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mu_liquid: 250e-6,
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mu_vapor: 11e-6,
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sigma: 0.011,
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};
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let qualities = [
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0.10, 0.50, 0.80, 0.90, 0.95, 0.97, 0.99, 0.995, 0.999, 0.9999, 1.0,
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];
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println!(
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"\n{:<10} {:<14} {:<14} {:<14}",
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"x", "MSH", "dMSH/dx", "Friedel"
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);
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let mut prev_msh: Option<f64> = None;
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let mut prev_x: Option<f64> = None;
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for &x in &qualities {
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let inp = FriedelInput { quality: x, ..base };
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let msh = msh_gradient(&inp);
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let fri = friedel_gradient(&inp);
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let dmsdh = match (prev_msh, prev_x) {
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(Some(pm), Some(px)) => (msh - pm) / (x - px),
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_ => f64::NAN,
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};
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println!("{:<10.5} {:<14.3} {:<14.3} {:<14.3}", x, msh, dmsdh, fri);
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prev_msh = Some(msh);
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prev_x = Some(x);
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}
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// Analytic derivative check: d/dx[linear·(1-x)^(1/3)] near x=1
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println!("\nAnalytic derivative of linear·(1-x)^(1/3) term:");
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let a: f64 =
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2.0 * 0.079 * (300.0_f64 * 0.0095 / 250e-6).powf(-0.25) * 300.0 * 300.0 / (0.0095 * 1290.0);
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let b: f64 =
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2.0 * 0.079 * (300.0_f64 * 0.0095 / 11e-6).powf(-0.25) * 300.0 * 300.0 / (0.0095 * 17.4);
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println!(" A = liquid-only gradient = {:.3} Pa/m", a);
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println!(" B = vapor-only gradient = {:.3} Pa/m", b);
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println!(" Ratio B/A = {:.1}", b / a);
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for &x in &[0.9_f64, 0.95, 0.99, 0.999, 0.9999] {
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let linear = a + 2.0 * (b - a) * x;
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let term = linear * (1.0 - x).powf(1.0 / 3.0);
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// d/dx[linear·(1-x)^(1/3)] = 2(b-a)·(1-x)^(1/3) - (1/3)·linear·(1-x)^(-2/3)
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let d_term = 2.0 * (b - a) * (1.0 - x).powf(1.0 / 3.0)
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- (1.0 / 3.0) * linear * (1.0 - x).powf(-2.0 / 3.0);
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let d_total = d_term + 3.0 * b * x * x;
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println!(
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" x={:.5}: term={:>10.2} d(term)/dx={:>14.2} d(MSH)/dx={:>14.2}",
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x, term, d_term, d_total
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);
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}
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}
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