Experimental Study on Lubrication Performance of Slide Bearing with Groove on All Pads

2011 ◽  
Vol 199-200 ◽  
pp. 659-669
Author(s):  
Yong Guo ◽  
Wei Jun Zhao ◽  
Ling Yang ◽  
Xiao Yang Yuan
Keyword(s):  
Experimental Study ◽  
Reynolds Number ◽  
Flow State ◽  
Specific Pressure ◽  
Work Condition ◽  
Number Range ◽  
Lubrication Performance ◽  
Speed Range ◽  
Lubricating Property ◽  
Temperature And Pressure

This paper reports a case of lubricating property test of bearing. In order to seize the performance and the reasonable work condition of Ф480mm elliptical bearing with groove on all pads for 1000MW steam turbine, an experimental method that load is on the rotor was adopted in this paper. And the test focused on the bearing characteristics which is most concerned by designers such as power loses, temperature, flow, and flow state, etc. The influence on power loses, temperature rise, flow by the temperature and pressure of inlet oil, load, speed was studied in this test. The results show that the flow state in this bearing is changed from laminar to turbulent in the speed range 2000rpm~2200rpm and in the Reynolds number range 1325.8~1556.5. The specific pressure for the bearing with groove on the down pad is proper between 1.57MPa and 1.96MPa.

Experimental Study of Advanced Convective Cooling Techniques for Combustor Liners

2008 ◽  
Author(s):  
Michael Maurer ◽  
Uwe Ruedel ◽  
Michael Gritsch ◽  
Jens von Wolfersdorf
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Reynolds Number ◽  
Heat Transfer Coefficient ◽  
Flow Field ◽  
Transfer Coefficient ◽  
Heat Transfer Enhancement ◽  
Transfer Enhancement ◽  
Number Range ◽  
Convective Cooling

An experimental study was conducted to determine the heat transfer performance of advanced convective cooling techniques at the typical conditions found in a backside cooled combustion chamber. For these internal cooling channels, the Reynolds number is usually found to be above the Reynolds number range covered by available databases in the open literature. As possible candidates for an improved convective cooling configuration in terms of heat transfer augmentation and acceptable pressure drops, W-shaped and WW-shaped ribs were considered for channels with a rectangular cross section. Additionally, uniformly distributed hemispheres were investigated. Here, four different roughness spacings were studied to identify the influence on friction factors and the heat transfer enhancement. The ribs and the hemispheres were placed on one channel wall only. Pressure losses and heat transfer enhancement data for all test cases are reported. To resolve the heat transfer coefficient, a transient thermocromic liquid crystal technique was applied. Additionally, the area-averaged heat transfer coefficient on the W-shaped rib itself was observed using the so-called lumped-heat capacitance method. To gain insight into the flow field and to reveal the important flow field structures, numerical computations were conducted with the commercial code FLUENT™.

Experimental Study of Lubricating Property at Grinding Wheel/Workpiece Interface Under NMQL Grinding

2020 ◽  
pp. 275-297
Keyword(s):  
Molecular Structure ◽  
Carbon Nanotubes ◽  
Experimental Study ◽  
Minimum Quantity Lubrication ◽  
High Viscosity ◽  
Lubricating Oil ◽  
Grinding Wheel ◽  
Oxide Nanoparticles ◽  
Lubrication Performance ◽  
Lubricating Property

Nanofluid is the suspension formed by lubricating oil and nanoparticles with particles sizes of 1~100 nm, and common nanoparticles include metal nanoparticles (Cu, Ag, etc.), oxide nanoparticles (Al2O3, SiO2, ZrO2, etc.), carbides (CNT, diamond), and MoS2 nanoparticles, etc. Different nanoparticles exhibit various physicochemical properties (e.g., structure and shape), which can influence their tribological characteristics. In this work, six nanofluids, namely, MoS2, SiO2, diamond, carbon nanotubes (CNTs), Al2O3, and ZrO2, were used as minimum quantity lubrication grinding fluids to select the kind of nanoparticles with optimum lubrication performance in grinding nickel alloy GH4169. Experimental results concluded the following: 1) Nanoparticles with spherical or sphere-like molecular structure and nanofluids with high viscosity demonstrate superior lubrication performances. 2) The polishing effect of nanodiamond particles enhances their surface morphology. 3) The lubricating property of the six nanofluids is described in the following order: ZrO2 < CNTs < ND < MoS2 < SiO2 < Al2O3.

Variable Reynolds Number Experimental Study on Aerodynamic Characteristic of Supercritical Airfoil RAE2822

2013 ◽  
Vol 420 ◽  
pp. 42-46
Author(s):  
Na Wang ◽  
Chao Gao
Keyword(s):  
Experimental Study ◽  
Reynolds Number ◽  
Wind Tunnel ◽  
Pressure Distribution ◽  
Pressure Coefficient ◽  
Lower Surface ◽  
Number Range ◽  
Moment Coefficient ◽  
Pressure Distributions ◽  
The Moment

An experimental study of pressure distributions over RAE2822 airfoil in the two-dimensional test section 0.8×0.4 meter of a transonic wind tunnel which is the first pressruized continuous wind tunnel in China is presented. This paper in order to further study the influence of the dynamic of continuous changes Reynolds number at Mach number is 0.66 and 0.80, and the attack angle is from-2 degree to 10 degree, and especially the Reynolds number range from3.0×106to 12×106. The study is focalized on the subsonic range of flow conditions with separation and shock wave in the boundary layer. The influence of pressure distribution and pressure coefficient and moment coefficient caused by Reynolds number increasing are analyzed and discussed. The conclusions showed that the pressure distribution of the lower surface of the airfoil get the influence of the Reynolds number is negligible. The Reynolds number impact on the pressure distribution is faintness at Ma=0.66. Reynolds number increases affect the airfoil central and trailing edge pressure. As the Reynolds number increases, the CL curve move and the gradient increasing. The moment coefficient decreased as the Reynolds number increasing. The CL curve with Cd curve moves left as Reynolds number increasing.

A Reassessment of Metering Orifices for Low Reynolds Numbers

1965 ◽  
Vol 180 (1) ◽  
pp. 331-356 ◽  
Author(s):  
L. J. Kastner ◽  
J. C. McVeigh
Keyword(s):  
Experimental Study ◽  
Reynolds Number ◽  
Flow Rate ◽  
Discharge Coefficient ◽  
Low Reynolds Number ◽  
Reynolds Numbers ◽  
Number Range ◽  
Low Reynolds Numbers ◽  
Discharge Coefficients ◽  
Low Reynolds

In view of the importance of accurate measurement of flow rate at low Reynolds numbers, there have been numerous attempts to develop metering devices having constant discharge coefficients in the range of pipe Reynolds numbers between about 3000 and 200 and even below this latter value, and some of these attempts have achieved a reasonable degrees of success. Nevertheless, some confusion exists regarding the dimensions and range of utility of certain designs which have been recommended and further information is necessary in order that the situation may be clarified. The aims of the present investigation, which is believed to be wider in scope than any published in this field in recent years, were to review and correlate existing knowledge and to make an experimental study of the properties of various types of orifice in the low range of Reynolds numbers. Arising from this it was hoped that a design might be evolved which not only had a satisfactorily constant discharge coefficient throughout the range but was also simple to manufacture and reproduce, even for small orifice diameters of the order of 0.5 in or less, and it is believed that some success in attaining this aim was achieved. The first section of the paper contains a review of previous investigations classified into three main groups. In the second part of the paper, experiments with various types of orifice plate are described and it is shown that a properly proportioned single-bevelled orifice has as good a performance in the low Reynolds number range as that of any of the more complicated shapes.

Turbulent Lubrication Flow in an Annular Channel

1986 ◽  
Vol 108 (2) ◽  
pp. 185-192 ◽  
Author(s):  
H. G. Polderman ◽  
G. Velraeds ◽  
W. Knol
Keyword(s):  
Experimental Study ◽  
Reynolds Number ◽  
Diffusion Model ◽  
Annular Channel ◽  
Velocity Profiles ◽  
Experimental Results ◽  
Wall Friction ◽  
Number Range ◽  
Gradient Diffusion ◽  
Good Agreement

An analytical and experimental study is presented of the lubrication flow in an annular channel with a moving core. Velocity profiles and wall friction were determined over a Reynolds number range up to 3 × 104 and radius ratios of 0.6 and 0.85. The experimental results are shown to be in good agreement with the predictions of a three-layer gradient-diffusion model.

scholarly journals An Experimental Study of Microchannel and Micro-Pin-Fin Based On-Chip Cooling Systems with Silicon-to-Silicon Direct Bonding

Sensors ◽  
2020 ◽  
Vol 20 (19) ◽  
pp. 5533
Author(s):  
Yunlong Qiu ◽  
Wenjie Hu ◽  
Changju Wu ◽  
Weifang Chen
Keyword(s):  
Experimental Study ◽  
Reynolds Number ◽  
Pressure Drop ◽  
Heat Sink ◽  
Cooling Systems ◽  
Number Range ◽  
Pin Fin ◽  
Chip Cooling ◽  
High Heat Transfer ◽  
On Chip

This paper describes an experimental study of the cooling capabilities of microchannel and micro-pin-fin based on-chip cooling systems. The on-chip cooling systems integrated with a micro heat sink, simulated power IC (integrated circuit) and temperature sensors are fabricated by micromachining and silicon-to-silicon direct bonding. Three micro heat sink structures: a microchannel heat sink (MCHS), an inline micro-pin-fin heat sink (I-MPFHS) and a staggered micro-pin-fin heat sink (S-MPFHS) are tested in the Reynolds number range of 79.2 to 882.3. The results show that S-MPFHS is preferred if the water pump can provide enough pressure drop. However, S-MPFHS has the worst performance when the rated pressure drop of the pump is lower than 1.5 kPa because the endwall effect under a low Reynolds number suppresses the disturbance generated by the staggered micro pin fins but S-MPFHS is still preferred when the rated pressure drop of the pump is in the range of 1.5 to 20 kPa. When the rated pressure drop of the pump is higher than 20 kPa, I-MPFHS will be the best choice because of high heat transfer enhancement and low pressure drop price brought by the unsteady vortex street.

scholarly journals Effect of Reynolds Number on a Plunging Airfoil

2020 ◽  
Author(s):  
Diana Carvalho Rodrigues ◽  
Emanuel António Rodrigues Camacho ◽  
Fernando Manuel da Silva Pereira Neves ◽  
André Resende Rodrigues Silva ◽  
Jorge Manuel Martins Barata
Keyword(s):  
Reynolds Number ◽  
New Technologies ◽  
Leading Edge ◽  
Aerodynamic Performance ◽  
Number Range ◽  
Diffusion Effects ◽  
Speed Range ◽  
Nature Frequency ◽  
Edge Vortex ◽  
Effective Angle

Biomimetics is an area of science that studies the development of new technologies, whose source of inspiration is Nature. Unlike traditional aircraft, animals only have one structure to create both lift and thrust, and for Humans, although in the recent years the studies in this area increased, a long way must be made to achieve their capability. The present paper focuses on the effect of the Reynolds number on the wake configuration produced by a plunging airfoil. The experimental work was performed using an airstream, that was marked with smoke, with an oscillating airfoil NACA0012, whose dimensions are 44cm and 10cm of span and aerodynamic chord, respectively. The motion prescribed for the wing is harmonic, since it very well represents the type of motion seen in Nature. Frequency and amplitude were maintained, respectively, at 1.2Hz and 2.8cm, and the wind speed range from 0.25m/s to 1.00m/s, which represents a nondimensional amplitude of 0.28, a reduced frequencies of 3.02, 1.51 and 0.75, and a Strouhal number and a Reynolds number range of, 0.07 – 0.27 and 1,500 – 6,300, respectively. Results indicate that, with the increase of the Reynolds number, the convection effects become more predominant than diffusion effects, the curvature of the wakes and the maximum effective angle of attack decrease, and time and configuration of vortex shedding change. For Re = 1,500, St = 0.27, another relevant conclusion appears; the interaction of the leading-edge vortex with the trailing-edge vortex indicates an improvement of the aerodynamic performance of this system. Keywords: Biomimetics, Plunging, Airfoil, Vortices, Wakes

Sign in / Sign up

Export Citation Format

Share Document