{"id":557288,"date":"2024-11-05T18:17:34","date_gmt":"2024-11-05T18:17:34","guid":{"rendered":"https:\/\/pdfstandards.shop\/product\/uncategorized\/esdu-030122010\/"},"modified":"2024-11-05T18:17:34","modified_gmt":"2024-11-05T18:17:34","slug":"esdu-030122010","status":"publish","type":"product","link":"https:\/\/pdfstandards.shop\/product\/publishers\/esdu\/esdu-030122010\/","title":{"rendered":"ESDU 03012:2010"},"content":{"rendered":"

INTRODUCTION<\/strong><\/p>\n

Design and performance analysis methods for ducted flow systems
\noften involve an explicit or implicit assumption that the flow is
\nuniform across a section. In practice, some degree of spatial
\nnon-uniformity is present in all real ducted flow systems and,
\nconsequently, it is often necessary to formulate a set of
\nrepresentative mean properties to describe a non-uniform flow and
\nto use in the analysis methods.<\/p>\n

The use of appropriate mean values is important, for example, in
\nthe calculation of component performance when the inlet and outlet
\nprofiles are significantly different and in cases where the
\nvariation of properties across a profile is large. Mean values are
\noften used to provide a simplified flow description at component
\ninterfaces and an appropriate choice is particularly important in
\nensuring consistency between calculations for separate components
\nof a system, such as a gas turbine engine, that may be analysed
\nindependently by different groups.<\/p>\n

This Data Item complements a group of Items concerned with the
\ndefinition of mean values and mean-value sets for the
\none-dimensional representation of steady, spatially non-uniform
\nflows and their use in the analysis of system performance.
\nReferences 5 and 7 are concerned primarily with definition of the
\nreference-mean<\/i> mean-value-set for compressible
\nflow*<\/sup>. If there are no constraints on the choice of mean
\nvalues, use of the reference-mean set is recommended . Its
\nprincipal advantages over historical approaches to flow averaging
\nare that it is thermodynamically-consistent, it retains the correct
\nsectional entropy and therefore allows a true measure of efficiency
\nfor processes in which profiles change, it is
\napplication-independent, providing a universal definition across
\ncomponent interfaces and it avoids attributing hypothetical losses
\nto the flow upstream or downstream of the measurement station. It
\nrequires no more input information than that required for any
\nmass-flow based method.<\/p>\n

The Data Item provides information on the use of, and background
\nto, a computer program for calculation of mean-value properties at
\na section in a duct flow. The methods are applicable to steady,
\nspatially non-uniform (profiled) compressible flows, assumed to be
\nessentially axial, i.e.<\/i> free from significant crossflows
\nsuch as radial flow and swirl. The flow property profiles may be
\nderived from experimental measurements, in which case measurement
\nuncertainties on the raw measurements are assumed to be accounted
\nfor separately so that the calculation starts with a "corrected"
\nset of measurements. Alternatively, the flow property profiles may
\nbe derived from computational fluid dynamics analysis methods or
\nspecified as analytical power-law profiles.<\/p>\n

Section 2 relates the notation used in output files from the
\nprogram to notation used in the text of the Data Items. Some
\nspecific terminology used to describe gas property calculations is
\nalso explained.<\/p>\n

Section 3 describes access to the program, which is available as
\nan executable file.<\/p>\n

The input data required by the program are described in Section
\n4. The program requires input of profile information for static
\npressure, total pressure or axial velocity and total temperature or
\nprofile definition by input of power-law parameters. The principal
\napplication is to radial profiles in circular or annular ducts and
\nprofiles across one direction only of rectangular ducts. However, a
\nmore general input option is included that allows for profiles
\nvarying in two dimensions and for other duct shapes.<\/p>\n

Output from the program is described in Section 5. The program
\ncalculates local property values across the profile and uses these
\nto derive sectionally-integrated values and mean values. Although
\nuse of the reference-mean-set<\/i> is recommended, the program
\ncalculates a wide range of mean-value properties from other
\ndefinitions for comparison with the reference-mean set and for
\ncontinuity with previously-used methods. The calculated mean values
\nfall into one of several groups as described below.<\/p>\n

\u2022 Mean property values that form part of thermodynamically
\nself-consistent mean-value-sets, notably the reference-mean values
\n(Appendix A.3).<\/p>\n

\u2022 Mean-set factors allowing the derivation of
\nsectionally-integrated extensive properties of the profiled flow
\nfrom the mean property values (Appendix A.3). A minimum number of
\nthese factors forms an essential part of any complete
\nmean-value-set.<\/p>\n

\u2022 Mean values that are part of groups for which, historically,
\nonly a few basic mean properties have been used, such as
\nmass-derived mean values. These groups have, where possible, been
\nextended to cover a full set of mean flow properties. Often the
\noriginal derivations were restricted to isenergic (uniform total
\ntemperature) flows of calorically-perfect gases. Again the methods
\nhave been extended to cover the more general case with
\ntotal-temperature profiles and for thermally-perfect gases where
\nthis is feasible (Appendix A.4).<\/p>\n

\u2022 Miscellaneous mean values that are derived from particular
\nmean-specific extensive properties, such as enthalpy-derived mean
\nvalues (Appendix A.5).<\/p>\n

\u2022 Profile factors relating two different mean-value definitions
\nof a particular property. These are useful in indicating the
\nmagnitudes of differences between definitions. In this program
\nthese profile factors nearly all use the reference-mean-set values
\nas the comparison (Appendices A.3, A.4, A.5).<\/p>\n

Two worked examples are described in Section 6, for which input
\nand output files are listed in Appendix D.<\/p>\n

Appendix A gives brief descriptions of the mean-value properties
\ncalculated. Appendix B lists the unit sets allowed in the program
\nand gives conversion factors and other default parameters included
\nwithin the program. Appendix C gives a glossary of some terms used
\nin the Item and related terms that may be encountered in the
\nliterature.<\/p>\n

* Reference 9 considers the application of the same methodology
\nto incompressible flows.<\/p>\n","protected":false},"excerpt":{"rendered":"

Computer Program for Calculation of Mean Value Properties for Non-Uniform Compressible Flows<\/b><\/p>\n\n\n\n\n
Published By<\/td>\nPublication Date<\/td>\nNumber of Pages<\/td>\n<\/tr>\n
ESDU<\/b><\/a><\/td>\n2010-06<\/td>\n69<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n","protected":false},"featured_media":557297,"template":"","meta":{"rank_math_lock_modified_date":false,"ep_exclude_from_search":false},"product_cat":[2675],"product_tag":[],"class_list":{"0":"post-557288","1":"product","2":"type-product","3":"status-publish","4":"has-post-thumbnail","6":"product_cat-esdu","8":"first","9":"instock","10":"sold-individually","11":"shipping-taxable","12":"purchasable","13":"product-type-simple"},"_links":{"self":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product\/557288","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/types\/product"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/media\/557297"}],"wp:attachment":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/media?parent=557288"}],"wp:term":[{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_cat?post=557288"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_tag?post=557288"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}