An unsteady state method for measuring the permeability of small tubular membranes

AIChE Journal ◽  
1975 ◽  
Vol 21 (6) ◽  
pp. 1192-1199 ◽  
Author(s):  
James F. Stevenson ◽  
Michael A. Von Deak ◽  
Mark Weinberg ◽  
R. Wade Schuette
Keyword(s):  
Unsteady State ◽  
State Method ◽  
Tubular Membranes

scholarly journals Assessment of enclosing structure moisture regime using moisture potential theory

2018 ◽  
Vol 193 ◽  
pp. 03053 ◽  
Author(s):  
Vladimir Gagarin ◽  
Vadim Akhmetov ◽  
Kirill Zubarev
Keyword(s):  
Mathematical Models ◽  
Potential Theory ◽  
Single Layer ◽  
Moisture Distribution ◽  
Moisture Regime ◽  
Continuous Control ◽  
Unsteady State ◽  
Steady State Method ◽  
State Method ◽  
Moisture Potential

The paper describes principal development directions of mathematical models of enclosing structure moisture regime. Benefits of mathematical models based on moisture potential theory are demonstrated. Moisture regime calculation by means of moisture potential, taking liquid and vapor moisture transfer into consideration, and using discrete-continual approach is proposed. New formulas for single-layer and multi-layer enclosing structures allowing for numerical analytic determination of moisture potential value in any enclosing structure section, at any moment of time, under continuous control of temperature distribution, have been derived. Moisture distribution has been studied for a number of enclosing structures using different methods of moisture potential theory: unsteady-state method, quasi-stationary method, the proposed discrete-continual method. Moisture regime has been determined for single-layer enclosing structure with ceramic brick basement and lime brick cladding in Moscow. It is shown that the greatest moisture value is achieved in enclosing structure calculation by means of steady-state method. Unsteady-state method gives more accurate moisture distribution. The proposed discrete-continual method gives quantitative and qualitative result of moisture distribution similar to results obtained by unsteady-state method. The benefit of discrete-continual method is a distribution obtained analytically, which allows to use solution results without numerical method application.

An unsteady state method for the measurement of polymer thermal diffusivity

2002 ◽  
Vol 38 (10) ◽  
pp. 2109-2117 ◽  
Author(s):  
J. Papa ◽  
C. Albano ◽  
W. Baré ◽  
O. Navarro ◽  
D. Galárraga ◽  
...  
Keyword(s):  
Thermal Diffusivity ◽  
Unsteady State ◽  
State Method

scholarly journals Determination of physical and thermophysical characteristics of red peppers (Capsicum annum) using unsteady-state method

2018 ◽  
Author(s):  
Siti Asmaniyah Mardiyani ◽  
Soemardi Hadi Sumarlan ◽  
Bambang Dwi Argo ◽  
Amin Setyo Laksono
Keyword(s):  
Unsteady State ◽  
Thermophysical Characteristics ◽  
Capsicum Annum ◽  
State Method ◽  
Red Peppers

Three-Phase Relative Permeability Measurements by Unsteady-State Method

1966 ◽  
Vol 6 (03) ◽  
pp. 199-205 ◽  
Author(s):  
A.M. Sarem
Keyword(s):  
Relative Permeability ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Unsteady State ◽  
Two Phase ◽  
Three Phase ◽  
Three Phase Flow ◽  
State Method ◽  
Permeability Data ◽  
Saturation History

Abstract For the performance prediction of multiphase oil recovery processes such as steam stimulation, there is an acute need for three-phase relative permeability data. No fast and simple experimental technique, such as the unsteady-state method proposed by Welge for two-phase flow, is available for the three-phase flow. In this paper, an unsteady-state method is presented for obtaining three-phase relative permeability data; this method is as fast and easy as Welge's method for two-phase flow. Analytical expressions are derived by extension of the Buckley-Leverett theory to three-phase flow to express the saturation at the outflow face for all three phases in terms of the known parameters. It is assumed that the fractional flow and relative permeability of each phase are a function of the saturation of that phase. Other simplifying assumptions made include the neglect of capillary and gravity effects. The effect of saturation history upon relative permeability is acknowledged and attainment of similar saturation history in laboratory and field is recommended. The required experimental work and computations are simple to perform. The test core is presaturated with oil and water, then subjected to gas drive. During the test, required data are the rates of oil, water, and gas production, together with pressure drop and temperature. The ordinary gas-oil unsteady-state relative permeability apparatus can be readily modified to measure the required data. The proposed technique was applied to samples of a Berea and a reservoir core. The effect of saturation history upon relative permeability was studied on one Berea core. It was found that increase in initial water saturation has a similar effect upon three-phase relative permeability as it does in two-phase flow. Introduction In the light of increasing demand for three-phase, relative permeability data for predicting the performance of thermal and other multiphase-flow recovery processes, a simple and accurate method of experimental determination of such data is extremely desirable. Leverett and Lewis1 described the simultaneous flow method of obtaining three-phase relative permeability data. However, Caudle et al.2 reported that this method is very time consuming and cumbersome. Corey3 proposed calculating the three-phase relative permeability from measured krg data. Corey's theory is based on simplified capillary pressure curves,4 assuming a straight line relationship between 1/Pc2 and saturation. Also, Corey's method assumes a preferentially water-wet system. The simplest and quickest method of obtaining three-phase relative permeability data is the unsteady-state method where, for instance, oil and water are displaced by gas. However, in such a test the correlation of average saturation with relative permeability does not give a valid relationship because the rates of oil, water and gas flow in the sample change continuously from the upstream to downstream end. This difficulty in calculating valid relationships was solved by Welge for two-phase flow by deriving an expression from Buckley and Leverett frontal advance equations.5,6 In this paper, relations are established to determine the outflow face saturation and relative permeability to all phases in a three-phase flow displacement experiment. Proposed Method The fundamentals established by Buckley and Leverett5 for two-phase flow were extended to three-phase flow and used as a basis for the derivation of saturation equations. This approach is comparable to Welge's6 use of Buckley and Leverett theory in arriving at expressions to determine the outflow face saturation of the displacing fluid in a two-phase flow system.

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