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Modelling, computation and performance animation of turbomachinery systems has recently enjoyed remarkable attention in CAD research. This is also reflected its application to exhaust machine components such as turbo loaders and the exceptionally novel pressure wave machine (Comprex) in the automobile industry and gas turbines. The necessity for the thermo‐fluidic performance animation of such pressure wave machines results from the fact that the machine geometry must be adapted to the technical and thermo‐fluidic properties of the exhaust flow of the gas turbine or automobile engine. Experimental adaptation or adjustment is costly and should be validated for every application case. Thus the potential to apply accurate animation for such shock‐tube like behaviour of compressible flow is now economically promising with a view to optimizing the design of the pressure wave machine. This paper presents briefly the problem oriented algorithms used and illustrates the performance animation of the pressure wave machine operating under constant speed drive. After introducing the pressure wave machine operation, the principles and summary of the algorithms used to compute the thermodynamic behaviour within the cell, the boundary models and the accuracy of computation. A Comprex cycle operating on an engine exhaust gas with T = 920°K, p = 2bar is illustrated through 3‐dimensional representations for pressure, speed of flow and temperature. The particle path (gas and air) together with time representation of the state variables at different points of the Compex will be shown. The mass balance problem is discussed and the conditions for mass balanced flow for the gas as well as for the air side are given. The results achieved for such materially balanced pressure wave machines indicate a reduction in the costs for subsequent experimental validation and to deliver the sound base for further development towards considering the pre‐balanced transient operation cases as well.

THE power output from an engine is roughly proportional to the absolute pressure of the charge mixture in the induction system. If we take a normally aspirated engine, the maximum power output is obtained when the induction pressure is raised to atmospheric pressure by opening the throttle to wide open. The power output may be lowered by reducing the induction pressures by part closing the throttle. The power output could be increased by supplying the induction gases at a pressure higher than atmospheric. This can be done by attaching a supercharger to the engine which, drawing air at atmospheric pressure, will deliver it to the induction system at a pressure higher than atmospheric, and the greater the pressure of delivery, the greater will be the power output.

The purpose of the paper is to analyze the bearing capacity of hydrostatic bearing during the change of film thickness under different working conditions and to improve the processing efficiency and precision of equipment.

In this study, Q1-205 double rectangular cavity hydrostatic thrust bearing is selected as the research object. The dynamic mesh method and ANSYS/FLUENT software are used to simulate the curves of oil film thickness and oil pressure under different operating conditions. Finally, the change of pressure in the oil cavity at different operating speeds under a certain inlet flow rate was tested through design experiments.

When the film thickness was thick, the maximum pressure in the oil cavity at different inlet velocities showed little difference. With a larger inlet flow, the maximum pressure in the oil cavity was higher. The pressure at the edge of the oil seal was linearly distributed. The oil pressure in the downstream side was greater than that in the counter flow side. When the working pressure was low, the pressure in the oil cavity slightly decreased with the increase of working speed. Moreover, the pressure loss at high speed was considerable.

Based on the lubrication theory, the mathematical model of the bearing oil film was set up. The bearing capacity equation of the hydrostatic cavity was derived. The double-rectangular-annular hydrostatic guides studied in this paper have not been reported in previous research literature and the method of dynamic mesh dynamic simulation of variable viscosity is seldom studied before. The bearing characteristics and the change of oil film thickness under different working conditions have been studied systematically and comprehensively. The theoretical analysis results are basically consistent with the experimental results.

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.

A point in the operation of journal bearings under hydrodynamic or thick film conditions which has always excited controversy is the question of the negative pressures predicted in the classical theory. This note examines relevant theoretical and experimental evidence of conditions in the low pressure regions in journal bearing oil films, referring particularly to possible cavitation phenomena and making suggestions for further research.

This paper aims to describe new measuring device designed for measuring the pressure exerted by textile products used in healing therapy of hypertrophic scars. The testing device called “Textilpress” has been used for verification of the usually used method of designing and manufacturing ready‐made compression garment products.

The pressure measurement, realized by use of the “Textilpress” device, is an indirect measuring method, which is based on the Laplace Law. The investigations described in this paper concern the pressure measuring under textile bands placed on the models representing selected parts of the human body with pre‐set circumferences. For this purpose, rigid cylinders were prepared, covered by a layer of neoprene which simulated the susceptibility of human skin.

The investigations described in this paper indicate that the “Textilpress” test‐device may be used for pressure measuring exerted by compression bands on the cylinder surface. In order to estimate the pressure exerted on a particular body part with the shape close to a cylinder, a measurement should be carried out on a cylinder with a circumference similar to that of the selected part of the human body.

The “Textilpress” test‐device may be used by the manufacturers for measuring pressures exerted by compression bands (manufactured from knitted fabrics) on the cylinder surface of a pre‐set diameter. In order to estimate the pressure exerted on a particular body part with the shape close to a cylinder, a measurement should be carried out on a cylinder with a circumference similar to that of the selected part of the human body.

As hospitals do not possess appropriate measuring devices, which would enable one to measure the pressure on the scar exerted by the textile garment, the pressure efficiency and the appropriate fittings are estimated subjectively for the particular case. The “Textilpress” device enables monitoring such pressure.

Thermal power plants have many problems regarding noise and vibration. Previous studies have shown that such problems are often related to the fans. However, the internal flows are difficult to analyze to find the cause of vibration and noise in fans in actual tests. Therefore, the unsteady internal flow field in a centrifugal fan was simulated numerical to identify the source. This paper aims to present these issues.

The unsteady Reynolds‐averaged Navier‐Stokes equations with the SST k‐ω turbulence model were solved to simulate the flow within the entire flow path of the fan. The conservation of mass and moment and energy equations were used to solve the flow field distribution. The time‐dependent pressure pulsations on the impeller were analyzed for the dynamics problem. The finite volume method with the SIMPLEC algorithm was used to discretize the time‐dependent equations. The second‐order upwind scheme was used for the convection terms and the central difference scheme was chosen for the diffusion terms in the momentum and transport equations.

The numerical simulations illustrated the flow characteristics inside the double suction centrifugal fan. The predicted efficiency is almost the same as the experimental value. The estimated pressure and temperature fields are quite reasonable. The results showed that the interaction between the non‐uniform impeller flow and the fixed volute aroused the significant pressure fluctuations, which is an important source of vibration and noise in centrifugal machinery.

It is assumed that there is no change in the density in the whole flow passage, and the predicted outlet temperature is about 1.15 per cent lower than the experimental result.

The simulation study indicates that the prediction of noise is possible by using pressure pulsation. It is recommended to control the pressure pulsation in the fans, to decrease the vibration and noise of thermal power plants.

Girdles should be designed to beautify the lower body part of a woman without creating any discomfort and detrimental physiological effects. This paper reports on an experimental investigation into the relationship between the subjective tightness sensation and the clothing pressure of girdles. The subjective tightness sensation is a measure of the effectiveness of girdles, since too loose means the girdle is not effective in shaping the body and too tight means it is not comfortable and may have detrimental physiological effects. Based on this experimental investigation, the effect of clothing pressure on the tightness sensation is better understood and the optimum pressure distribution of girdles, which is an important criterion for product development and evaluation of girdles, is proposed.

This study aims to clarify the key factors among physical‐mechanical properties of fabrics in relation to the dynamic pressure performance of compression garment.

The physical‐mechanical properties of 16 different fabrics were measured using a KESF standard evaluation system and INSTRON tensile tester, and the garment pressure was measured by dynamic pressure measuring system. Grey correlation analysis is used to determine the correlation degree of fabric physical‐mechanical properties and dynamic pressure magnitude.

The mechanical behaviors (e.g. tensile, shearing, and bending) and physical characteristics are different in elastic fabrics with varied content of elastic fiber, kinds of yarn, et al. Grey correlation analysis is a valid method to analyze the indices of a system, quantize them and put them in order. All the degrees of Grey correlation are more than 0.6. The degree of grey correlation between tensile force (F), shearing rigidity (G) and bending rigidity (B) are higher than others, hence it is conducted that these would significantly effect on garment pressure. The quantitative regression equations between pressure magnitude at extension of 50 percent and the individual key parameters (mean values in wale and course directions) of tested samples are illustrated.

The other parameters (e.g. fabric structure, yarn fineness, and pre‐tension, et al.) should be taken into account. Further, an integrative mathematic model would be established, which could predict the garment pressure directly from the physical‐mechanical properties of fabric.

The present study indicates that pressure magnitude of elastic fabric is an integrative action performed by physical‐mechanical properties. The developed illustrative equations and method offer a rational and practical tool for assessing pressure functional performance of elastic fabric in the stages of design and product development.

The flexibly thin film grid pressure sensor is mainly used to detect the interface pressure distribution between touching objects. Aim at larger measurement error, the strip double sensing layer pressure sensor are designed and fabricated and tested.

Defects and characteristic of the flexibly thin film grid pressure sensor based on piezoresistive effect are analyzed and pointed out in this paper. After comparison of four sensors, the strip double sensing layer pressure sensor was thought to be best.

Experiment shows that the strip double sensing layer pressure sensor could eliminate the measurement error basically and illustrates the validity of measuring the interface pressure distribution between area touching objects.

In this paper, only the strip double sensing layer pressure sensor was used to verify the validity of measuring the static interface pressure distribution between peach and platform. But there also exists some problems such as the adhering reliability of electrode and the unevenness of sensing layer. These problems could be overcome in the future research if the fabricating procedure and ingredient of material could be adjusted correctly.

The strip double sensing layer pressure sensor could be applied to detect the static interface pressure distribution such as peach pressure distribution. For dynamic measurement, this research needs to be done further.

Strip double sensing layer pressure sensor with simple “interlayer” structure and with low manufacture cost is presented to basically eliminate the measurement error of interface pressure distribution of original sensor.