Periodic longitudinal flows of pseudoplastic materials

A model is studied in the full range of all operational parameters of the unsteady plane flow of a power-law liquid induced by periodically variable pressure drop and oscillatory motion of the walls of a plane duct. Using the theory of similariry criteria of the asymptotic behaviour are formulated in four qualitatively different rheodynamic regimes. Corresponding asymptotic expressions are found for the degree of mechanical liquidization by the action of oscillatory shear stress superimposed on the principal steady state component. Theoretical results are illustrated using a set of experimental data on the gravitational flow along a vertical oscillating sheet.

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CALCULATION METHODS OF VARIABLE PRESSURE-DROP FLOWMETERS ACCURACY IMPROVEMENT

Scientific Papers Collection of the Angarsk State Technical University ◽

10.36629/2686-7788-2018-1-1-88-92 ◽

2018 ◽

Vol 1 (1) ◽

pp. 88-92

Author(s):

I.L. Ilina ◽

◽

A.I. Noskova ◽

Keyword(s):

Pressure Drop ◽

Variable Pressure ◽

Calculation Methods ◽

Accuracy Improvement ◽

Variable Pressure Drop

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Analysis of a New Mixed Finite Volume Method

Computational Methods in Applied Mathematics ◽

10.2478/cmam-2003-0013 ◽

2003 ◽

Vol 3 (1) ◽

pp. 189-201 ◽

Cited By ~ 5

Author(s):

Ilya D. Mishev

Keyword(s):

Finite Volume Method ◽

Finite Volume ◽

Elliptic Equations ◽

Variable Pressure ◽

Order Error ◽

First Order ◽

Scalar Variable ◽

Volume Method ◽

Well Posed ◽

Theoretical Results

AbstractA new mixed finite volume method for elliptic equations with tensor coefficients on rectangular meshes (2 and 3-D) is presented. The implementation of the discretization as a finite volume method for the scalar variable (“pressure”) is derived. The scheme is well suited for heterogeneous and anisotropic media because of the generalized harmonic averaging. It is shown that the method is stable and well posed. First-order error estimates are derived. The theoretical results are confirmed by the presented numerical experiments.

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Computer Modelling For 4-Stroke Direct Injection Diesel Engine

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.33-37.801 ◽

2008 ◽

Vol 33-37 ◽

pp. 801-806

Author(s):

Abdul Rahim Ismail ◽

Rosli Abu Bakar ◽

Semin Ali ◽

Ismail Ali

Keyword(s):

Diesel Engine ◽

Simulation Study ◽

Engine Speed ◽

Computer Modelling ◽

Direct Injection ◽

One Dimension ◽

Effective Pressure ◽

Operational Parameters ◽

Direct Injection Diesel Engine ◽

Theoretical Results

Study on computational modeling of 4-stroke single cylinder direct injection diesel engine is presented. The engine with known specification is being modeled using one dimension CFD GT-Power software. The operational parameters of the engine such as power, torque, specific fuel consumption and mean effective pressure which are dependent to engine speed are being discussed. The results from the simulation study are compared with the theoretical results to get the true trend of the results.

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Solution of the inverse problem of parameter conversion of variable pressure drop flowmeters

Measurement Techniques ◽

10.1007/bf00865870 ◽

1987 ◽

Vol 30 (2) ◽

pp. 167-169

Author(s):

E. P. Pistun ◽

I. S. Kruk ◽

L. V. Lesovoi

Keyword(s):

Inverse Problem ◽

Pressure Drop ◽

Variable Pressure ◽

Parameter Conversion ◽

Variable Pressure Drop

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Practical Considerations for Forecasting Production Data in Unconventional Reservoirs — Variable Pressure Drop Case

10.2118/170945-ms ◽

2014 ◽

Cited By ~ 2

Author(s):

Patrick Collins ◽

Dilhan Ilk ◽

Thomas Alwin Blasingame

Keyword(s):

Pressure Drop ◽

Unconventional Reservoirs ◽

Variable Pressure ◽

Production Data ◽

Variable Pressure Drop

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Integrated approach to assessment of impact of beyond-design modes on operation of steam supply systems

Safety and Reliability of Power Industry ◽

10.24223/1999-5555-2019-12-1-10-17 ◽

2019 ◽

Vol 12 (1) ◽

pp. 10-17 ◽

Cited By ~ 1

Author(s):

A. I. Kiseleva ◽

A. M. Fokin

Keyword(s):

Integrated Approach ◽

Maximum Load ◽

Variable Pressure ◽

Methodological Error ◽

Individual Element ◽

Steam Extraction ◽

Condensation Mode ◽

Network Quality ◽

Supply Systems ◽

Variable Pressure Drop

The object of the study are the steam networks of Smolensk. The purpose of the article is to determine the influence of beyond-design modes on the functioning of the entire steam supply system. Beyond-design modes of industrial steam supply pose a serious problem for all elements of the system: they make it difficult to fully load the turbines, lead to high excess losses of heat and coolant, and also lead to disruption in technological processes. Analysis of statistical data on reduction of industrial steam extraction has been carried out, archived data on heat supply and consumption have been processed and analyzed over the period from 2007 to 2017. A methodological error is found in the accounting of thermal energy and coolant by variable pressure drop flowmeters designed to handle superheated and dry steam. Calculation of heat network quality indicators is carried out, maximum permissible lengths of steam pipeline sections are determined, enabling to transport superheated steam to consumer regardless of the load reduction. The influence of the extent of wear of insulation and the diameter of the pipeline on the change in the aggregate state of the coolant has been analyzed, and the maximum load for steam networks has been found as being 30% of the designed one. It has been established that, with industrial extraction decreased, the CHPP is forced to disengage the turbine from operation, since a load drop of more than 50% brings the turbine to the condensation mode and reduces the technical and economic performance of the CHPP to the threshold permissible values. The obtained results enable to draw a conclusion that such a problem as beyond-design modes, especially in steam supply systems, requires an integrated approach, since the influence on an individual element in isolation from the system leads to a change in the performance of the remaining elements.

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Model prediction for constant area, variable pressure drop in orifice plate characteristics in flow system

10.31221/osf.io/638zq ◽

2019 ◽

Author(s):

Chem Int

Keyword(s):

Pressure Drop ◽

Flow Rate ◽

Mathematic Model ◽

Pressure Change ◽

Orifice Plate ◽

Variable Pressure ◽

Pd Controller ◽

Constant Area ◽

Variable Pressure Drop ◽

Derivative Control

The effect of density, pressure drop, viscosity and orifice area on the characteristics of fluid flow was examined in this paper. Also studied was the effect on the control pressure change of the constant area variable pressure drop meter as a proportional derivative control. The mathematical model developed to monitor and predict the control of the system is given as P-Po = 7.8/t – 0.06 + Kc +Kd. The change in control pressure decreases with increase in proportional/derivative gain (Kc, Kd) as well as increase in time. The Bernoulli’s principle was applied in describing the design principle, stability analysis and development of mathematic model of a pressure-based flow meter with a constant area, variable pressure drop; using an orifice plate with different fluid flowing through it. The developed formula relates pressure drop with the flow rate of a given fluid passing through the orifice. The formula obtained is then simulated using different fluids. In order to control the flow rate, of these fluid flowing through the model developed was related to a Proportional Derivative control (PD). Thereby getting knowledge on how the PD controller performs with respect to different fluids, with change in pressure, density and area of the pipe/orifice was presented in this paper. Finally information and results on the simulation and how the PD controller functional parameters of proportional gain and derivative gain influence the control system was examined in this research.

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Things That Go “Bump” in the VPSEM - and How We Image with Them

Microscopy and Microanalysis ◽

10.1017/s1431927600029937 ◽

2001 ◽

Vol 7 (S2) ◽

pp. 772-773

Author(s):

Brendan J Griffin

Keyword(s):

Secondary Electron ◽

Full Range ◽

High Vacuum ◽

Electron Interaction ◽

Variable Pressure ◽

Imaging Model ◽

Wide Range ◽

Electron Microscopes ◽

Electron Imaging ◽

Scanning Electron Microscopes

Variable pressure scanning electron microscopes (VPSEM) differ from conventional SEM by operating at pressures ranging from the ‘high vacuum’ SEM levels of 10-6 torr up to typically around 2 torr. The environmental SEM or ESEM is a commercial variant which employs an unique multistage pressure-limiting aperture (PLA) system to attain specimen chamber operating pressures of up to 50 torr. Early instruments used air or argon as the imaging gas but more commonly today water vapour is used. A wide range of gases have been employed, including potentially explosive hydrogen-methane mixtures. The choice of gas is operator-based and can be varied during the imaging session.Early VPESM were restricted to backscattered electron imaging (BSE) until the development of the gaseous secondary electron detector in the ESEM. Gaseous secondary electron detectors are now available for all models of VPSEM and together with compatible cathodoluminescence and EDS XRay detectors, the full range of SEM-based imaging options is present.The principal distinguishing feature of VPSEM is, of course, that samples can be examined uncoated. Gas-electron interaction generates a positive ion supply that can minimise conventional charging artefacts, in a simple imaging model.

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