Experimental Study on Hybrid Gas Bearing with Water Evaporation from Ultra-fine Porous Medium

This paper describes findings obtained to date in the area of journal gas bearings from an experimental study of a Brayton cycle turbocompressor designed for the requirements of a two-shaft 10-kw space power system. The journal bearing design utilizes three pads pivoted on conforming balls and sockets. Two of the pivots are rigidly mounted to the frame, and the third pivot is mounted to the frame through a low-spring-rate diaphragm. This paper describes the salient package and bearing design features and then presents the principal results obtained from testing the package in both a spin calibration rig and operation at design temperature conditions with an inert gas. The results discussed include (a) the successful use of a pneumatic loading device to vary pad load during operation, (b) the operating characteristics of the bearings as obtained over a range of pad loads and ambient conditions, (c) structural and dynamic behavior of the bearing-support system during design temperature operation and (d) a discussion of the wear characteristics of the conforming ball-and-socket pivot as obtained from the tests made to date.

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An experimental study of secondary oil migration in a three-dimensional tilted porous medium

AAPG Bulletin ◽

10.1306/09091110140 ◽

2012 ◽

Vol 96 (5) ◽

pp. 773-788 ◽

Cited By ~ 11

Author(s):

Jianzhao Yan ◽

Xiaorong Luo ◽

Weimin Wang ◽

Renaud Toussaint ◽

Jean Schmittbuhl ◽

...

Keyword(s):

Experimental Study ◽

Porous Medium ◽

Three Dimensional ◽

Oil Migration

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An Experimental Study on Microscopic Flow Over and Inside Porous Medium Placed on Oscillatory Flow

Journal of Japan Society of Civil Engineers Ser B2 (Coastal Engineering) ◽

10.2208/kaigan.69.i_36 ◽

2013 ◽

Vol 69 (2) ◽

pp. I_36-I_40

Author(s):

Yuuya OKADA ◽

Takaaki SHIGEMATSU ◽

Sota NAKAJO

Keyword(s):

Experimental Study ◽

Porous Medium ◽

Oscillatory Flow ◽

Microscopic Flow

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Cortex Effect on Vacuum Drying Process of Porous Medium

Mathematical Problems in Engineering ◽

10.1155/2013/120736 ◽

2013 ◽

Vol 2013 ◽

pp. 1-8 ◽

Cited By ~ 1

Author(s):

Zhijun Zhang ◽

Shiwei Zhang ◽

Tianyi Su ◽

Shuangshuang Zhao

Keyword(s):

Mass Transfer ◽

Porous Medium ◽

Fruits And Vegetables ◽

Water Saturation ◽

Coupled Model ◽

Water Evaporation ◽

Vacuum Drying ◽

Vapor Pressures ◽

Drying Process ◽

Medium Vacuum

Corns, fruits, and vegetables are usually used as porous medium in drying process. But in fact, it must be considered as the cortex effect on mass transfer because the mass transfer of cortex is very difficult than inner medium. Based on the theory of heat and mass transfer, a coupled model for the porous medium vacuum drying process with cortex effect is constructed. The model is implemented and solved using COMSOL software. The water evaporation rate is determined using a nonequilibrium method with the rate constant parameterKrthat has been studied. The effects of different vapor pressures (1000, 5000, and 9000 Pa), initial moisture contents (0.3, 0.4, and 0.5 water saturation), drying temperatures (323, 333, and 343 K), and intrinsic permeability for cortex part (10−13, 10−14, 10−15 m2) on vacuum drying process were studied. The results facilitate a better understanding of the porous medium vacuum drying process that nearer to the reality.

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Experimental Study of the Effect of Curing Mode on Concreting in Hot Weather

Revue des composites et des matériaux avancés ◽

10.18280/rcma.310408 ◽

2021 ◽

Vol 31 (4) ◽

pp. 243-248

Author(s):

Nassima Bakir

Keyword(s):

Experimental Study ◽

Concrete Surface ◽

Work Conditions ◽

Climatic Conditions ◽

Water Evaporation ◽

Negative Effects ◽

Climate Conditions ◽

Hot Climate ◽

Hot Weather ◽

Job Site

Most developing countries have hot climate, ordinary jobsites characterized by reduced of human resources, equipment and infrastructures. The objective of this article is to make an experimental study of the influence of the hot climate such as that of Algeria, on the different properties of concrete in the fresh state, such as excessive water evaporation from the concrete surface, increased demand for water, increased slump loss corresponding to additional water on job-site, higher plastic shrinkage cracking and difficulty in controlling air content. At the hardened state, we could mention a reduction of strength at 28 days, decreased durability resulting from cracking at long-term period. To show the problems linked to concreting under these conditions and to present the appropriate solutions concrete or mortar can withstand the conditions in which it is implemented. Thus, negative effects caused principally by hot weather concreting motivated the choice of the such study. The research experimental work conditions in which the cementitious matrix was kept concerned two different environments, namely hot and dry climate conditions (t = 40°, h = 0%) alike the climate of the region of M'sila., and that of a medium with a hot and humid environment (t = 40°, h = 100%). The output of the investigation demonstrated the crucial role of the cure method in hot regions. The comparison of results for a reference concrete kept in air without any curing measures with two curing types simulating hot weather environment of the region M’sila was undertaken. These obtained outcome results were discussed based on the influence of climatic conditions to conclude procedures for hot weather concreting and suitable cure methods.

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