ESDU 82009
Compressible flow of gases. Pressure losses and discharge coefficients of orifice plates, perforated plates and thick orifice plates in ducts.
Abstract:
ESDU 82009 provides pressure loss and discharge coefficient data for subsonic compressible flow of gases through single, or multiple, sharp-edged orifices in thin or thick plates for flow rates up to choking. The mechanics of compressible flow through orifices are discussed briefly with particular attention to sonic flow conditions. The mass flow function, based on orifice entry conditions, that gives maximum mass flow rate is defined and pressure loss coefficients are then expressed as a function of the ratio of the actual mass flow function to that limiting value. All are functions also of porosity and thickness/diameter ratio of the orifice. The data cover a range of porosity between 0.001 and 0.95 and thickness/diameter up to seven. Discharge coefficients are presented for orifices of very small porosity, for maximum mass flow conditions and for conditions when the total-pressure loss coefficient exceeds unity. Although the data were derived for symmetrical arrangements of circular holes in circular plates they can be applied reasonably well to square ducts, square holes and small departures from symmetry. A computer program, ESDUpac A8209, is provided.Indexed under:
- Choking Conditions in Duct Flow
- Discharge Coefficient
- Orifices
- Perforated Plates
- Pressure Drop Across Obstructions in Ducts
- Pressure Drop in Internal Flow
Details:
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This Data Item is complemented by the following software:
| Name | Details | ||||
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ESDUpac A8209 |
This program is only available to subscribers. |
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This Data Item contains 17 interactive graph(s) as listed below.
| Graph | Title |
|---|---|
| Figure 1 | Effect of porosity on incompressible flow pressure-loss coefficient for t/d = 0 and 0.8 |
| Figure 2 | Correction factor for effect of t/d ratio on incompressible flow pressure-loss coefficient, K'0 for separated flow |
| Figure 3 | Correction factor for effect of t/d and α on incompressible flow pressure-loss coefficient, K'0.8 for reattached flow |
| Figure 4 | Mean mass flow function at entry to orifice at which maximum mass flow rate occurs for t/d < 0.8, γ = 1.4 |
| Figure 5 | Mean mass flow function at entry to orifice at which maximum mass flow rate occurs for t/d ≥ 0.8, γ = 1.4 |
| Figure 6 | Compressibility correction factor for total-pressure loss for 0 < α < 0.95, 0 < t/d < 0.7 and γ = 1.4 |
| Figure 7 | Compressibility correction factor for total-pressure loss for t/d < 0.8, γ = 1.4 |
| Figure 8 | Compressibility correction factor for total-pressure loss for t/d ≥ 0.8, γ = 1.4 |
| Figure 9 | Compressibility correction factor for static-pressure drop for αq*2 ≈ 0, γ = 1.4 |
| Figure 10 | Compressibility correction factor, γ = 1.4 |
| Figure 11 | Effect of mass flow function and total-pressure loss coefficient on discharge coefficient for kt > 1, 0 < t/d < 7.0 and γ = 1.4 |
| Figure 12 | Effect of mass flow function and t/d ratio on discharge coefficient for α ≈ 0, t/d < 0.8 and γ = 1.4 |
| Figure 13 - Part 1 | Effect of mass flow function and t/d ratio on discharge coefficient for α ≈ 0, t/d ≥ 0.8 and γ = 1.4 |
| Figure 13 - Part 2 | Effect of mass flow function and t/d ratio on discharge coefficient for α ≈ 0, t/d ≥ 0.8 and γ = 1.4 |
| Figure A1 | Effect of mass flow function on static to total pressure ratio, γ = 1.4 |
| Figure B1 | Mean value of discharge coefficient that gives maximum mass flow rate for t/d < 0.8, γ = 1.4 |
| Figure B2 | Mean value of discharge coefficient that gives maximum mass flow rate for t/d ≥ 0.8, γ = 1.4 |