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The paper concerns numerical analysis of pressure distribution of an oil film on the valve plate in the variable height gap of an axial piston pump. The analysis employs the finite element method. For determination of oil pressure variations in the gap, the Reynolds equation, commonly applied in the theory of lubrication, is applied. The equation is solved numerically with the use of self-developed program based on the finite element method. In order to obtain high accuracy of the results, an adaptive mesh refinement based on residual estimations of solution errors is applied. The calculation results are represented as dependent on the geometric and working parameters of the pump. 相似文献
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Rovere Pierpaolo Nicoletta Squarcina Secondo Gola Luca Sandei Stefania Iametti Giuseppe Carpi 《高压研究》2013,33(1-6):99-107
Abstract It is known that pressure alone is not able to make shelf-stable any food stored in room conditions. Acid products are normally spoiled by enzymes, and low acid products are spoiled even by spore-forming micro-organisms. To overcome the problem the role of heat in the process has been re-evaluated and the possibility of destroying at the same time spores and enzymes has been found. This work compares the effect of sterilisation by High Pressure Processing (HPP) with one of the conventional retort processing techniques. Two batches of meat sauce were kept in room conditions over a year and their quality was evaluated periodically during the shelf life simulation. The physico-chemical characteristics of the retorted ones showed a progressive appearance of the typical thermal damage. The High Pressure Sterilised samples on the contrary showed limited damage, related to the unavoidable pre-heating. Their quality markers were constant over the shelf life evaluated period. 相似文献
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Arkadiusz J. Antończak Bogusz Stępak Paweł E. Kozioł Krzysztof M. Abramski 《Applied Physics A: Materials Science & Processing》2014,115(3):1003-1013
This paper presents the results of the measurements and analysis of the influence of laser process parameters on the color obtained. The study was conducted for titanium (Grade 2) using a commercially available industrial pulsed fiber laser. It was determined how a variety of different laser process parameters, such as laser power, the scanning speed of the material, the temperature of the material, the size of the marked area, and the position of the sample, relative to both the focal plane and the center of the working field of the system, affect the repeatability of the colors created. For an objective assessment of color changes, an optical spectrometer and the CIE color difference parameter $\Delta E_{ab}^{*}$ were used. Our paper explains why the tolerance of process parameters highly depends on the specific color. Additionally, a comparison of the results for titanium with those obtained for stainless steel in a previous study is presented. Based on this analysis, a number of necessary modifications are proposed to laser systems commonly used for monochrome marking in order to improve repeatability in color marking. 相似文献