# ISO 4022-1993

Disclosure to Promote the Right To InformationWhereas the Parliament of India has set out to provide a practical regime of right to information for citizens to secure access to information under the control of public authorities, in order to promote transparency and accountability in the working of every public authority, and whereas the attached publication of the Bureau of Indian Standards is of particular interest to the public, particularly disadvantaged communities and those engaged in the pursuit of education and knowledge, the attached public safety standard is made available to promote the timely dissemination of this information in an accurate manner to the public. इंटरनेट मानक“!ान $ एक न’ भारत का +नम-ण”Satyanarayan Gangaram Pitroda“Invent a New India Using Knowledge”“प0रा1 को छोड न’ 5 तरफ”Jawaharlal Nehru“Step Out From the Old to the New”“जान1 का अ+धकार, जी1 का अ+धकार”Mazdoor Kisan Shakti Sangathan“The Right to Information, The Right to Live”“!ान एक ऐसा खजाना जो कभी च0राया नहB जा सकता है”Bhartṛhari—Nītiśatakam“Knowledge is such a treasure which cannot be stolen”ैIS 13782 (1993): Permeable sintered metal materials -Determination of fluid permeability [MTD 25: PowderMetallurgical Materials and Products]IS 13782 : 1993 IS0 4022:1987 1 Indian Standard PERMEABLE SINTERED METAL MATERIALS - DETERMINATION OF FLUID PERMEABILITY UDC 669-138 8 : 620 193 19 @ BIS 1993 BUREAU OF INDIAN STANDARDS MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG NEW DELHI 110002 June 1993 Price Group 5 Powder Metallurgical Materials and Products Sectional Committee, MTD 25 NATIONAL FOREWORD This Indian Standard which is identical with IS0 4022 : 1987 ‘Permeable sintered metal materials - Determination of fluid permeability’, issued by the International Organization for Standardization ( IS0 ), was adopted by the Bureau of Indian Standards on the recommendations of the Powder Metallurgical Materials and Products Sectional Committee ( MTD 25 ) and approval of the Metallurgical Engineering Division Council. The text of IS0 Standard has been approved as suitable for publication as Indian Standard without deviations. Some terminology and conventions are, however, not identical with those used in Indian Standards. Attention is especially drawn to the following: a) Wherever the words ‘International Standard’ appear, referring to this standard, it should be read as ‘Indian Standard’. b) Comma ( , ) has been used as a decimal marker while in Indian Standards the current practice is to use a point ( . ) as the decimal marker. In this adopted standard, reference appears to IS0 2738. The Indian Standard IS 5642 : 1991 ‘Permeable sintered metal materials - Determination of density, oil content and open porosity ( second revision )‘. which is identical with IS0 2738 : 1987, is to be substituted in its place. In reporting the results of a test made in accordance with this standard, if the final value, observed or calculated, is to be rounded off, it shall be done in accordance with IS 2 : 1960 “Rules for rounding off numerical values ( revised )‘. IS 13782 : 1993 IS0 4022 : 1987 Indian Standard PERMEABLE SINTERED METAL MATERIALS - DETERMINATION OF FLUID PERMEABILITY 1 Scope and field of application This International Standard specifies a method for the deter- mination of the fluid permeability of permeable sintered metal materials in which the porosity is deliberately continuous or in- terconnecting, testing being carried out under such conditions that the fluid permeability can be expressed in terms of viscous and inertia permeability coefficients (see annex A). This International Standard does not apply to very long hollow cylindrical test pieces of small diameter, in which the pressure drop of the fluid in passing along the bore of the cylinder may not be negligible compared with the pressure drop of the fluid passing through the wall thickness (see annex A, clause A.5). 2 Reference IS0 2738, Permeable sintered metal materiels - Determination of density, oil content and open porosity. 3 Principle Passage of a test fluid of known viscosity and density through a test piece, and measurement of the pressure drop and the volumetric flow rate. Determination of the viscous and inertia permeability coeffi- cients, which are parameters of a formula describing the rela- tionship between the pressure drop, the volumetric flow rate, the viscosity and density of the test fluid, and the dimensions of the porous metal test piece permeated by this fluid. IS13782: 1993 IS0 4022 : 1987 4 Symbols and definitions For the purposes of this International Standard, the symbols and definitions given in the table apply: Table - Symbols and definitions Term 1 Symbol 1 Definition Unit Permeability Test area Thickness Length Viscous permeability coefficient Inertia permeability coefficient _ Ability of a porous metal to pass a fluid under the action of a _ pressure gradient A Area of a porous metal normal tc the direction of the fluid flow m2 e Dimension of the test piece in the direction of fluid flow a) for flat test pieces: equal to the thickness m b) for hollow cylinders: given by the equation in 6.1.2 L Length of cylinder lsee figure 2) m W” Volume flow rate at which a fluid of unit viscosity is transmitted through unit area of porous metal permeated under the action of unit pressure gradient when the resistance to fluid flow is due only m2 to viscous losses. It is independent of the quantity of porous metal considered. (//I Volume flow rate at which a fluid of unit density is transmitted through unit area of porous metal permeated under the action of unit pressure gradient when the resistance to fluid flow is due only rn. to inertia losses. It is independent of the quantity of porous metal considered. Volume flow rate Upstream pressure Downstream pressure Mean pressure Pressure drop Pressure gradient Velocity Density Dynamic viscosity Apparatus correction (to be subtracted from the observed pressure drop) Mean absolute temperature Q Mass flow rate of the fluid divided by irs density m3/s Pl Pressure upstrean of the test piece P2 Pressure downstream of the test piece N/m2 P Half the sum of the upstream and downstream pressures AP Difference between the pressures on the upstream and down- stream surfaces of the porous test piece N/m* Aple Pressure drop divided by the thickness of porous test piece N/m3 @IA Ratio of the volumetric flow rate to the t* I Pressure drop across porous metal Q,=Q2 Cl Pa=P2 J Line b D, = D, = Qz = PO = P3 = P2 - PO = PI - P2 = Figure 1 - Guard ring test head 3 IS 13782 : 1993 IS0 4022 : 1987 leads to atmosphere via a pressure-equalizing valve. This valve is adjusted to equalize the pressure in the inner and outer chambers. The fitting of a restrictor between the test piece and the flowmeter, to increase the back pressure and thus permit more stable control of the pressure-equalizing valve, is allowed. However, ideal - calculate the mean flow rate through the test piece; - determine the density and the viscosity of the test fluid. 8 Expression of results measured. 8.1 Mean flow rate 7.1.2 Hollow cylindrical test pieces For hollow cylinders, the thickness e and the test area A are The reading of the flowmeter Qr is corrected if it is not being given by the following relationships: used at its calibration pressure and temperature, by using the flowmeter correction factor Cr given by the manufacturer. The 02 - 4 ‘corrected flowmeter reading Q, is given by the following equa- e tion : 2 e = D x (In 42 2 (r - I) KxDitLxlnr A= r-l where r = $ (see figure 2) L)-d When the wall thickness - 2 is small-compared with d, for example less than 0,l d, the thickness e and test area A are given by the following equations: Q, = C, x Qf The corrected flowmeter reading Q, is converted to the mean flow rate Q within the porous test piece using the correction term C,, which can be calculated from the gas law equation: The mean flow rate is Q = C, x Q,. When tabulating data, it is convenient to use the overall correc- tion factor C,: c, = Cf x c, D-d e=------- 2 to obtain the mean flow rate Q = C, x Of. x x L x (D f d) A= 8.2 Mean density and viscosity 2 7.2 Measurement of pressure drop The mean pressure and the mean absolute temperature within the test piece will enable mean density and mean viscosity to be obtained from ljublished data. The pressure drop may be determined either by measuring the upstream and downstream pressures separately and taking the difference or by using a differential pressure gauge. 8.3 Calculation of results The apparatus correction is obtained by using the equipment with no test piece in place and observing the pressure drop over the required range of flow rates. The apparatus correction should preferably not exceed 10 % of the pressure drop (see the table). The viscous and inertia permeability coefficients are determined by taking a number of simultaneous flow rate and pressure drop readings. The number of flow rate readings shall be at least five, equally spaced within an interval of flow rate readings where the highest is at least ten times greater than the lowest. 7.3 Measurement of flow rate The results are processed using the following equation: A primary standard for the measurement of the flow rate of the test fluid is preferred. The flow rate shall be corrected to the Ap x A 1 QXP 1 mean pressure and temperature of the test piece. However, a exQxr] =G x-----+- Axq wv ’ standard flowmeter (previously calibrated against a primary standard) may be more convenient to use. [see annex A, equation (211. 5 IS 13782 : 1993 IS0 4022 : 1987 ‘, ‘5. This equation can be re-written in the form y = U.Y f h where Vxe x’=- Axrl The values x and y are calculated at each level of flow rate/pressure drop. The corresponding values of x and y are plotted on linear graph paper and the straight line which best fits the points is drawn. The intercept of this line on the y-axis gives the reciprocal of the viscous permeability (f/y/J. The slope of this line gives the reciprocal of the inertia permeability (1 /ryJ. In case of doubt, the straight line should be determined by the least-squares method. NOTE - If measurement is made with flow in the laminar regime, only the viscous permeability coefficient can be determined (see annex A). 8.4 Final result Report of the viscous permeability coefficient in 10 12 m2 (1 pm9 and the inertia permeability coefficient in 10 6 m (1 f_tm). to an accuracy of f 5 % in relative value. NOTE ~ The unit of viscous permeability coefficient (micrometre squared) is sometimes called a darcy. 9 Test report The test report shall include the following information : a) reference to this International Standard; b) all details necessary for identification of the test sample; c) the type of apparatus used; d) the test fluid used; e) the result obtained; f) all operations not specified by this International Stan dard or regarded as optional; g) details of any occurrence which may have affected the result. 6 IS13782:1993 lS04022:1987 “ Annex A The flow of fluid through porous materials (This annex does not form an integral part of the Standard.) A.1 Viscous flow The empirical formula for the flow of fluids through porous materials was first given by Darcv, followlng experiments with water, and expresses the proportionality between the pressure drop per unrt thickness and the flow rate per unit area and the vrscosttv. lt can be written 1) and assumes that the losses are all due to viscous shear A.2 Viscous and inertia flow In reality, the flow of fluid through porous materials can involve several mechanisms, many of whrch can be operating simultaneously However, experience shows that in the majority of cases involving the flow of fluids through porous metals only three mechanisms are usually involved. They are: viscous flow, inertia flow and slip flow. Inertia flow concerns the loss of energy due to the changes in the direction of the fluid in passing through tortuous porosity and to the onset of local turbulences in the pores, and has been combineci with the viscous loss equation of Darcy by Fotchheimer to give the equation (slip flow usually absent) AP Qxrl Q2 x P -=-+ e A x wv A2 x I//, . 121 which is used in 8.3 of this International Standard. However, at low velocities of flow (Q/,-l 1 of viscous fluids, the lnertla term of equa- tion (2) is usually insignificant compared with the viscous term and can he ignored to give the simpler equation (1). A.3 Slip flow Equation (1) assumes that the pore size IS large compared with the mean free path of the molecules of the test flurd. Thjs assumntlnn is most likely to be invalid with a very small pore sue and with gases at reduced pressure or high temperature When the mea,) free path of the gas molecules approaches the same order of size as the pores of the metal, shp flow occurs. When slip flow is present, the porous metal appears to be more permeable than when slip flow is absent. Also, when SII~ flow is present, inertia losses arc usually absent, so that equation (2) may be written In the form where tys is the permeability coefficient with slip flow present. The correction for slip flow is given by where 13) V’, is the observed viscous permeability with slip flow present; wv is the true VISCOUS permeability coefficrent; B is the Klinkenberg factor, which is a constant for a given gas and porous material, and has the dlmensrons of a pressure 7 IS 13782 : 1993 IS0 4022 : 1987 This relationship between wS and rc/v may be re-written in the form + WV . . . (5) n L Hence, by measuring (c/~ over a range of different pressures (i.e., p1 and - the end effect at the upstream and downstream surfaces of all test pieces. In general with granular materials, if the diameter of the test piece is not less than about 100 times the diameter of the parti’cles com- prising the porous metal, the wall effect is usually negligible and with a test piece diameter of about 40 times the particle diameter, the error is less than about 5 %. End effects are usually negligible when the test piece thickness is not less than 10 times the diameter of the particles comprising the porous metal. As in the case of the wall effect, the end effect also depends upon the difference between the porosity at the surface and the internal porosity. A.5 Long tubes of porous materials Equation (2) (see A.2) and the calculation of area and thickness in 7.1.2, as well as the measurement of the pressure drop in 7.2, assume that the upstream pressure is uniform for all parts of the specimen. With long small bore tubes this assumption may not be valid. To establish that the error caused by the fall in pressure of the fluid along the bore of the tube is less than 5 %, the following procedures can be used: a) Insert a second pressure tapping at the end furthest from the fluid iniet, and compare this value with the value obtained from the pressure tapping nearest to the fluid inlet. b) Mask about half of the area of the tube from one end. Measure the permea