INTRODUCTION

This Technical Note provides a review of the data in the literature for incompressible flow through orifice plates published prior to 2006. At that time ESDU 81039 provided correlations for the prediction of pressure loss across orifice plates and perforated plates for liquids in turbulent flow. These correlations did not cover a wide range of the geometry and flow parameters affecting the flow through orifice plates²⁴¹. This Technical Note was developed to aid the extension and improvement of those correlations.

The reviewed data were used in the validation of the CFD predictions carried out by ESDU to assist the development of the new correlations. The data found in the literature included measurements and numerical predictions of the flow field and pressure distribution over the orifice test pipe, pressure drops across the orifice plate and pressure loss and discharge coefficients data. A considerable part of these data was available from measurements in orifice flow-meters and in support of their international standards, i.e. ISO 5167²⁰¹, ASME MFC-3M²¹⁴and ANSI/API 2530¹⁵⁷. These standards can be accessed by subscribers at the IHS Engineering Resource Center, http:\www.ihserc.com, and are summarized in Note FI152²⁴³. However, the geometry and flow ranges of the data reviewed in this Technical Note are beyond the industry standards for flow measurement.

In this Technical Note, the geometry and flow characteristics in orifice plates are described in Section 3. Definitions for the pressure loss coefficient and discharge coefficient are given in Sections 4 and 5, respectively. The standard requirements for the discharge coefficient measurement in orifice flow-meters are summarized in Sections 5.2, 5.2.1 and 5.2.2. The data for incompressible flow of liquids are reviewed in Section 6 and summarized in Table A1.1 in Appendix A. These data include correlations for the pressure loss and discharge coefficients in Sections 6.3 and 6.5, which are also summarized in Tables B1.1 to B2.2 in Appendix B.

The consistency of the data in the literature for the downstream separation length and the pressure loss and discharge coefficients is discussed in Section 7. The effects of non-standard flow, operation and installation conditions are discussed in Section 8.