Source : Kubrak et al., Water 2022, 14, 3107 (open access, CC BY 4.0), table 1 and figure 5
When a steel pipe is extended with HDPE, the pressure rise drops as the HDPE length grows. After a single adjustment on the all-steel pipe, does CBELIER predict the pressure rise of the six other configurations?
A pressurised 48.1 m test rig: 53 mm steel on the reservoir side, HDPE on the valve side, in varying proportions (7 configurations). The valve closes quickly; the maximum pressure rise relative to the initial head, ΔHmax/H0, is compared.
| Data | Value | Status |
|---|---|---|
| Total length; steel lengths LS | 48.1 m; table 1 | PUBLISHED |
| Steel: D, wave speed | 53 mm; 1,195 m/s | PUBLISHED |
| HDPE: wave speed; Kelvin-Voigt J, τ | 300 m/s; 2.2·10⁻¹⁰ Pa⁻¹, 0.034 s | PUBLISHED |
| Flow; initial head | 0.917 L/s; 42 m | PUBLISHED |
| HDPE diameter: 32 mm written, 35.3 mm derived from the velocities | both | DERIVED |
| Measured ΔHmax/H0 (figure 5, ± 0.02) | 7 | READ FROM FIGURE |
| Closure time tc, on configuration no. 7 (steel only) | 0.1 s | CALIBRATED |
| Indicator | CBELIER | Reference | Difference |
|---|---|---|---|
| Maximum predicted difference, no. 1 to 6, HDPE 32 mm | 5.1 % | — | target 10 % |
| Maximum predicted difference, no. 1 to 6, HDPE 35.3 mm | 9.2 % | — | target 10 % |
| Configuration no. 1 (most HDPE), 32 mm | 1.84 | 1.75 | 5.1 % |
After a single adjustment on the all-steel pipe, the six other configurations are predicted within 5 % with the written diameter (32 mm) and within 9 % with the derived diameter (35.3 mm). The trend (lower pressure rise with longer HDPE) is reproduced.