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Avoid possible divide by zero in hydcoeffs.c

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Lew Rossman
2018-12-04 09:50:01 -05:00
parent 9ff0056b7c
commit 107483bee8
1 changed files with 19 additions and 8 deletions
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27
src/hydcoeffs.c
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@@ -799,21 +799,32 @@ void pumpcoeff(Project *pr, int k)
// Adjust head loss coefficients for pump speed // Adjust head loss coefficients for pump speed
h0 = SQR(setting) * pump->H0; h0 = SQR(setting) * pump->H0;
n = pump->N; n = pump->N;
if (ABS(n - 1.0) < TINY) n = 1.0;
r = pump->R * pow(setting, 2.0 - n); r = pump->R * pow(setting, 2.0 - n);
// Compute head loss and its gradient // Compute head loss and its gradient
// ... use linear approx. to pump curve for small flows // ... pump curve is nonlinear
qa = pow(hyd->RQtol / n / r, 1.0 / (n - 1.0)); if (n != 1.0)
if (q <= qa)
{ {
hgrad = hyd->RQtol; // ... use linear approx. to pump curve for small flows
hloss = h0 + hgrad * hyd->LinkFlow[k]; qa = pow(hyd->RQtol / n / r, 1.0 / (n - 1.0));
if (q <= qa)
{
hgrad = hyd->RQtol;
hloss = h0 + hgrad * hyd->LinkFlow[k];
}
// ... use original pump curve for normal flows
else
{
hgrad = n * r * pow(q, n - 1.0);
hloss = h0 + hgrad * hyd->LinkFlow[k] / n;
}
} }
// ... use original pump curve for normal flows // ... pump curve is linear
else else
{ {
hgrad = n * r * pow(q, n - 1.0); hgrad = r;
hloss = h0 + hgrad * hyd->LinkFlow[k] / n; hloss = h0 + hgrad * hyd->LinkFlow[k];
} }
} }