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The purpose of this paper is to find a solution of laminar liquid flow in asymmetric narrow channels. In many cases, an intuitive solution is much more useful and necessary for engineering applications, although numerical solutions can be obtained.

The Navier‐Stokes equations of laminar liquid flow in asymmetric narrow channels are simplified based on geometric characteristics of narrow channels, physical characteristics of liquid and boundary conditions. The simplified Navier‐Stokes equations are solved theoretically. Verification of the obtained results is carried out based on comparing with the Jeffery‐Hamel flow, which is an exact solution of liquid flow in convergent or divergent channels proposed by Jeffery.

This paper proposed an intuitive solution of laminar liquid flow in asymmetric narrow channels. Obtained results show that the solution can provide a fairly precise flowrate, when a ratio between the width of the channel and the curvature of the boundary of the asymmetry channel is smaller than 0.2936/Re. Furthermore, the obtained solution of pressure distribution along the channel shows high enough accuracy, even though the Reynolds number reaches to higher than 105.

Because the authors assumed the width of the channel is far smaller than the curvature of the boundary of the asymmetric channel, the obtained results could only fit finite cases. Because the Navier‐Stocks equations were finally simplified into one‐dimensional, it is impossible to forecast separation flows; so the obtained results will fail when the Re number is too big. However, experiments should be carried out further to verify these problems.

This paper proposes an intuitive solution of laminar liquid flow in asymmetric narrow channels, including the pressure distribution along the channel.

This paper aims to present a novel wireless passive pressure sensor based on an aperture coupled microstrip patch antenna embedded with an air cavity for pressure measurement.

In this paper, the sensitive membrane deformed when pressure was applied on the surface of the sensor and the relative permittivity of the mixed substrate changed, resulting in a change in the center frequency of the microstrip antenna. The size of the pressure sensor is determined by theoretical calculation and software simulation. Then, the sensor is fabricated separately as three layers using printed circuit board technology and glued together at last. The pressure test of the sensor is carried out in a sealed metal tank.

The extracted resonant frequency was found to monotonically shift from 2.219 to 1.974 GHz when the pressure varied from 0 to 300 kPa, leading to an average absolute sensitivity of 0.817 MHz/kPa.

This pressure sensor proposed here is mainly to verify the feasibility of this wireless passive maneuvering structure, and when the base material of this structure is replaced with some high-temperature-resistant material, the sensor can be used to measure the pressure inside the aircraft engine.

The sensor structure proposed here can be used to test the pressure in a high-temperature environment when the base material is replaced with some high-temperature-resistant material.

The purpose of this paper is to investigate flow behavior of electrorheological (ER) fluid in a closed piston–cylinder system.

A basic study of flow characteristics of ER fluid in a damper model is conducted experimentally and numerically. The electric field is applied between inner wall of the cylinder and outer wall of the piston, and the pressure difference between upper and lower chamber of the cylinder is measured. A numerical prediction of ER fluid flow in the damper model system is performed in order to study the ER fluid flow characteristics. Visualization experiment is also made and used to qualitatively verify the numerical formulation.

The agreement between the numerical predictions and experimental results is encouraging, and the ER fluid flow patterns under different piston aspect ratios, movement speeds and applied electric field strengths are presented. The results show that the piston aspect ratio has much smaller influence on the ER flow pattern than other influencing factors. Increasing piston movement speed or reducing the electric field applied is helpful to reduce the pressure response time period, which is an important indicator showing sensitiveness of the damper. It is also seen that the pressure difference between the upper and lower chamber of the cylinder increases with the electric field strength and the piston movement speed.

First time the detailed investigation into the hydrodynamics behavior in such working models of engineering applications for ER fluid.

The purpose of this paper is to focus on the application of the Trefftz method to the calculation of the two-dimensional (2D) temperature field in the boiling refrigerant flow through an asymmetrically heated vertical minichannel with a rectangular cross-section. The considerations were limited to determining the temperature of the continuous phase – liquid for bubbly and bubbly-slug flow. The numerical solution found with the Trefftz methods was compared with the simplified solution. For nucleate boiling, heat transfer coefficient at the heating foil – liquid contact was determined.

The Trefftz method was used to determine 2D temperature distributions for the glass pane, the heating foil and the boiling liquid. The temperature fields were approximated by the sum of the particular solution and the linear combination of suitable Trefftz functions. Coefficients of linear combination were computed using experimental data, including heating foil temperature measurements obtained with the liquid-crystal method and experimentally determined void fraction. The computations were based on the Trefftz method supplemented with the adjustment calculus.

The way of solving direct and inverse problems of heat conduction in solid bodies (isolating glass, heating foil) and in liquids (boiling refrigerant flowing through the minichannel) was presented. For the first time, both 2D temperature fields for the heating foil and the boiling liquid were calculated while simultaneously using the Trefftz method. The known temperature values of the foil and liquid allowed the calculation of the heat transfer coefficient and the heat flux at the heating foil-liquid contact. Adjustment calculus implemented into the Trefftz method was used to smooth the measurement data and to reduce their errors.

The approach proposed in the paper can be applied to determining 2D temperature field, heat flux and heat transfer coefficient in direct and inverse problems concerning two-phase flowing miniature compact heat exchangers.

The paper presents a novel implementation of the Trefftz method to simultaneous solving an inverse problem in the heating foil and the contacting flowing liquid.

Examines the wide range of liquid and solid level sensors, their technologies and commercial application.

Provides background information on trends in level sensing, on how each type works and the various applications. Some selection criteria are given.

There is a wide range of level sensors for every target liquid and solid sensing application, but the sector is technologically mature. There are some new application areas deriving from legislation and climate change.

Provides information of value for those involved with sensor applications.

The purpose of this paper is to investigate oil-gas slug formation in horizontal straight pipe and its associated pressure gradient, slug liquid holdup and slug frequency.

The abrupt change in gas/liquid velocities, which causes transition of flow patterns, was analyzed using incompressible volume of fluid method to capture the dynamic gas-liquid interface. The validity of present model and its methodology was validated using Baker’s flow regime chart for 3.15 inches diameter horizontal pipe and with existing experimental data to ensure its correctness.

The present paper proposes simplified correlations for liquid holdup and slug frequency by comparison with numerous existing models. The paper also identified correlations that can be used in operational oil and gas industry and several outlier models that may not be applicable.

The correlation may be limited to the range of material properties used in this paper.

Numerically derived liquid holdup and holdup frequency agreed reasonably with the experimentally derived correlations.

The models could be used to design pipeline and piping systems for oil and gas production.

The paper simulated all the seven flow regimes with superior results compared to existing methodology. New correlations derived numerically are compared to published experimental correlations to understand the difference between models.

Oil film thickness measurements made in the front main bearing of an operating 3.8 L, V‐6 engine were compared with rheological measurements made on a series of commercial and experimental oil blends. High‐temperature, high‐shear‐rate viscosity measurements correlated with the film thickness of all single‐grade and many multigrade oils. However, the film thickness provided by some multigrade oils were larger than could be accounted for by their high‐temperature, high‐shear‐rate viscosities alone. Although the pressure/viscosity coefficients of some of the oils were significantly different from those of the majority of oils tested, they were not oils which produced unusual film thicknesses. As a consequence, correcting oil viscosities for the esimated pressures acting within the bearing was unsuccessful in improving the correlations. The correlations were improved, however, by accounting for the elastic properties of the multigrade oils. Measurements of oil relaxation times at high temperatures and shear rates showed large differences in elastic properties among the test oils. A good correlation (R2 = 0.73) was obtained from a multiple linear regression of film thickness as a function of both high‐temperature, high‐shear‐rate viscosities and relaxation times.

Seeks to study the dependence of the shear strength of a fluid on the fluid pressure and the bulk fluid temperature, respectively, theoretically for given bulk fluid temperatures and fluid pressures in the whole ranges of fluid pressure and bulk fluid temperature.

The analyses are, respectively, carried out with emphasis on the dependence of the shear strength of a fluid in liquid state, i.e. at low pressures on the fluid pressure and the bulk fluid temperature for given bulk fluid temperatures and fluid pressures based on the theory of the compression of the fluid by the pressurization of the fluid.

The fluid shear strength versus fluid pressure curve in the whole range of fluid pressure and the fluid shear strength versus bulk fluid temperature curve in the whole range of bulk fluid temperature, respectively, for a given bulk fluid temperature and a given fluid pressure are obtained. It is shown by this fluid shear strength versus fluid pressure curve that, for a given bulk fluid temperature, when the fluid is in liquid state, i.e. at low pressures, the value of the shear strength of the fluid is insensitive to the variation of the pressure of the fluid and is low: when the fluid is in solidification state, i.e. at medium and high but not extremely high pressures, the value of the shear strength of the fluid is the most sensitive to the variation of the pressure of the fluid and is very approximately linearly increased with the increase of the pressure of the fluid; when the fluid is in high solidification state, i.e. at extremely high pressures, the value of the shear strength of the fluid is insensitive to the variation of the pressure of the fluid and is the highest, i.e. approaches the value of the shear strength of the fluid in solid state.

Extends one's knowledge of the shear strength of a fluid in the while ranges of pressure and temperature.

The National Engineering Laboratory is one of the larger stations of the British Government's Department of Scientific and Industrial Research. Current programmes include theoretical and experimental studies of non‐Newtonian lubricants, the development of new methods of measuring the compressibility of hydraulic fluids, research into the behaviour of oils under hydrostatic tension, and investigations of various aspects of the phenomenon of aeration in hydraulic fluids. The Laboratory's facilities for carrying out sponsored research and testing in this field are briefly described.

The purpose of this paper is to describe a procedure to simulate impact-driven liquid jets by computational fluid dynamics (CFD). The proposed CFD model is used to investigate nozzle flow behavior under ultra-high injection pressure and jet velocities generated by the impact driven method (IDM).

A CFD technique was employed to simulate the jet generation process. The injection process was simulated by using a two-phase flow mixture model, while the projectile motion was modeled the moving mesh technique. CFD results were compared with experimental results from jets generated by the IDM.

The paper provides a procedure to simulate impact-driven liquid jets by CFD. The validation shows reasonable agreement to previous experimental results. The pressure fluctuations inside the nozzle cavity strongly affect the liquid jet formation. The average jet velocity and the injection pressure depends mainly on the impact momentum and the volume of liquid in the nozzle, while the nozzle flow behavior (pressure fluctuation) depends mainly on the liquid volume and the impact velocity.

Results may slightly deviate from the actual phenomena due to two assumptions which are the liquid compressibility depends only on the rate of change of pressure respected to the liquid volume and the super cavitation process in the generation process is not taken into account.

Results from this study will be useful for further designs of the nozzle and impact conditions for applications of jet cutting, jet penetration, needle free injection, or any related areas.

This study presents the first success of employing a commercial code with additional user defined function to calculate the complex phenomena in the nozzle flow and jet injection generated by the IDM.