{"id":559864,"date":"2024-11-05T18:25:25","date_gmt":"2024-11-05T18:25:25","guid":{"rendered":"https:\/\/pdfstandards.shop\/product\/uncategorized\/esdu-tm-1482004\/"},"modified":"2024-11-05T18:25:25","modified_gmt":"2024-11-05T18:25:25","slug":"esdu-tm-1482004","status":"publish","type":"product","link":"https:\/\/pdfstandards.shop\/product\/publishers\/esdu\/esdu-tm-1482004\/","title":{"rendered":"ESDU TM 148:2004"},"content":{"rendered":"

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

where ^p<\/i> is the change in static or total pressure
\nbetween two reference sections and qref<\/sub><\/i> is a
\nreference kinetic pressure or dynamic pressure. This definition
\nimplicitly assumes that the flow at the reference sections is
\nuniform or one-dimensional.<\/p>\n

In contrast to the fundamental definition, the interpretation of
\nmeasurements from experiment or computation uses measurements made
\nin flow that will usually not be uniform at either the measurement
\nsections or the reference section.<\/p>\n

This Note explores the implications of this dichotomy which
\nleads to the need to make choices in the derivation of a
\npressure-loss coefficient when deriving one from experiment or
\ncomputation or a requirement to know what choices were made in the
\nderivation when applying given loss coefficients. The essential
\nrequirement is to define appropriate mean values to represent the
\nprofiled flow in a onedimensional manner.<\/p>\n

Given a profile of a property across a section in a flow, mean
\nvalues of that property can be defined in various
\nways3,4,6.<\/sup> The magnitude of the differences between the
\ndifferent mean values depends on the severity of the profile (and
\nfor some definitions, on the severity of other profiles). It is not
\npossible to define a set of mean property values that, on their
\nown, fully represent the profiled flow, a minimum number of
\nmean-set factors relating sectional properties to their mean-set
\nvalues is always required as well.<\/p>\n

In the present context the profiles are defined to be for
\nfully-developed axial flow. For fully-developed laminar flow,
\ndifferences between different definitions can be large but for
\nfull-developed turbulent flow smaller differences result. However,
\neven in turbulent flow these differences can contribute
\nsignificantly to the apparent spread between experimental results
\nfrom different sources and to the uncertainty of predicted pressure
\nlosses.<\/p>\n

For flow of an incompressible fluid, the value taken for
\nqref<\/sub><\/i> is the kinetic pressure
\n\u00bdP<\/sub>V<\/i>2<\/sup>. The kinetic 2 pressure is
\nconventionally assumed to be equal to the dynamic pressure
\n(pt<\/sub> – p<\/i>) but this is only universally true in
\none-dimensional flow, for other cases equality will depend on
\ncompatible definition of mean pt and mean V2<\/sup><\/i>
\n.<\/p>\n

This note focuses primarily on derivation or application of
\n"standard" pressure loss coefficients for which the flow at the
\nmeasurement sections is a fully-developed axial flow. The
\nderivation applies for flow of incompressible fluids, the case of
\ncompressible fluids is more complex and will be considered
\nelsewhere.<\/p>\n","protected":false},"excerpt":{"rendered":"

The Implications of Flow Property Profiles on Determination and Application of Non-Dimensional Pressure Loss Coefficients for Flow of Incompressible Fluids<\/b><\/p>\n\n\n\n\n
Published By<\/td>\nPublication Date<\/td>\nNumber of Pages<\/td>\n<\/tr>\n
ESDU<\/b><\/a><\/td>\n2004-09<\/td>\n45<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n","protected":false},"featured_media":559875,"template":"","meta":{"rank_math_lock_modified_date":false,"ep_exclude_from_search":false},"product_cat":[2675],"product_tag":[],"class_list":{"0":"post-559864","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\/559864","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\/559875"}],"wp:attachment":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/media?parent=559864"}],"wp:term":[{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_cat?post=559864"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_tag?post=559864"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}