The flow of a Newtonian lubricant in a clearance of a curvilinear thrust hydrostatic bearing with one porous wall is considered. The bearing is modelled by two curvilinear smooth surfaces and the porous wall is adhered to the curve non-porous surface. The flow in the bearing clearance is considered with inertia forces and the Navier-Stokes and Poisson equations are uncoupled by using the Morgan-Cameron approximation. The equations of motion are solved by an averaged inertia method. Step and spherical bearings are discussed as examples. It shown that the inertia effects influence the bearing performance considerably.
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The flow of a power-law lubricant in a squeeze film bearing with one porous wall is considered. The bearing is modelled by two curvilinear rough surfaces and the porous wall is adheres to the curved non-porous surface. The flow in the bearing clearance is considered without inertia and the Navier-Stokes and Poisson equations are uncoupled by using the Morgan-Cameron approximation. Using the Christensen stochastic model of a surface roughness a closed-form solution is obtained. A step bearing and a spherical bearing are discussed as examples. It is shown that the power-law exponent and the roughness influence the bearing performance considerably.
Inertia effects in the flow of suspension modelled as a power-law fluid in a curvilinear squeeze film channel with the porous pad were considered. The analysis was based on the assumption that the porous pad consisted of a system of capillaries of very small radii, which allowed the use of the Darcy law and the Mor-gan-Cameron approximation for the flow in the porous pad. A spherical channel was discussed as an example.
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Reliable cooling of thermally high stressed components in the field of thrust chamber and turbine technology requires the use of more effective cooling techniques compared to the common recuperative cooling. Alternative cooling techniques basing on mass transfer through the wall such as transpiration cooling are available. For thermal design of transpiration cooled components a detailed knowledge with respect especially to the convective heat transfer behavior in the hot gas boundary layer on the porous wall is requested. This paper describes experimental investigations on this problem as well as the modeling of the measuring results by means of empirical correlations for engineering purposes.
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The flow of a power-law lubricant in a squeeze film bearing with one porous wall is considered. The bearing is modelled by two curvilinear surfaces and the porous wall is adhered to the curved non-porous surface. The flow in the bearing clearance is considered with inertia and the Navier-Stokes and Poisson equations are uncoupled by using the Morgan-Cameron approximation. Using the averaged inertia method the closed-form solution is obtained. A step bearing is discussed as an example.
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The flow of a Newtonian fluid in squeeze film of a biological bearing with one porous wall is considered. The bearing is modelled by two curvilinear surfaces and the porous wall is adhered to the curved non-porous surface. The flow in the bearing clearance is considered with inertia and the Navier-Stokes and Poisson equations are uncoupled by using the Morgan-Cameron approximation. Using the averaged inertia method the closed-form solution is obtained. Step and spherical bearings are discussed as examples.
PL
Rozważano przepływ cieczy newtonowskiej w ściskanym filmie biologicznego łożyska z jedną porowatą ścianką. Łożysko jest modelowane przez dwie krzywoliniowe powierzchnie. Porowata ścianka przylega do krzywoliniowej nieporowatej powierzchni. Rozważony jest przepływ cieczy w przestrzeni łożyska z uwzględnieniem bezwładności. Równania Naviera-Stokesa i Poissona są rozwiązane z zastosowaniem przybliżenia Morgana-Camerona. Z wykorzystaniem metody uśredniania bezwładności zostało uzyskane rozwiązanie w formie zamkniętej. Przykładowo zostały rozpatrzone łożyska stopowe i sferyczne.
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Zanalizowano stan termiczno-wilgotnościowy przegrody budowlanej znajdującej się w otoczeniu wilgotnego powietrza o zadanej temperaturze i wilgotności względnej. Rozważania przeprowadzono na podstawie modelu suszenia opracowanego wcześniej przez autorów. Ich przedmiotem była dwumetrowa ściana o przekroju prostokątnym, w pełni zawilżona od strony fundamentów i dobrze izolowana w górnej części. Stwierdzono, że efekt suszenia ściany wiąże się z utratą ciepła na odparowanie i przez to obniża jej temperaturę. Niska temperatura ściany ochładza pomieszczenie mieszkalne i w tym sensie jej własności termoizolacyjne są gorsze niż suchej ściany.
EN
The influence of temperature and relative moisture content of air surrounding wet wall on its temperature and moisture content is analysed. The considerations are based on the drying model constructed earlier by the authors. A wali of rectangular cross-section and 2 m in height, being fully saturated at the foundation footing and effectively insulated at the top, was the object of interest. Drying of the wali by the surrounding air causes the loss of heat for evaporation and thus drop of the wali temperature. A wall of Iow temperature cooles inhabited room and in that sense the thermal insulation properties of wet wali are worse than those of dry one.
The influence of the wall porosity on the pressure distribution of a Shvedov-Bingham fluid flowing in the clearance between two surfaces of revolution is considered. As a result one obtains the formulae expressing the pressure distribution. An example of a squeeze flow between parallel disks is discussed in detail.
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