A Calculation Method to Investigate the Effects of Geometric Parameters and Operational Conditions on the Static Characteristics of Aerostatic Spherical Bearings

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Hailong Cui ◽  
Huan Xia ◽  
Dajiang Lei ◽  
Xinjiang Zhang ◽  
Zhengyi Jiang
Keyword(s):  
Experimental Data ◽  
Calculation Method ◽  
Reynolds Equation ◽  
Geometric Parameters ◽  
Static Characteristics ◽  
Optimal Parameters ◽  
Film Pressure ◽  
Operational Conditions ◽  
Pressure Distributions ◽  
Calculation Results

In this paper, a calculation method based on matlab partial differential equations (PDE) tool is proposed to investigate the static characteristics of aerostatic spherical bearings. The Reynolds equation of aerostatic spherical bearings is transformed into a standard elliptic equation. The effects of geometric parameters and operational conditions on the film pressure, bearing film force, and stiffness are studied. The axial and radial eccentricities result in different film pressure distributions; the bearing film force and stiffness are significantly influenced by geometric parameters and operational conditions. The relative optimal parameters are confirmed based on the calculation results. A comparison between the numerical and experimental results is also presented. The highest relative error between the numerical results and the experimental data is 11.3%; the calculation results show good agreements with the experimental data, thus verifying the accuracy of the calculation method used in this paper.

scholarly journals To Calculation Of Bended Elements Working Under The Conditions Of Exposure To High And High Temperatures On The Lateral Force By A New Method

2021 ◽  
Vol 03 (05) ◽  
pp. 210-218
Author(s):  
Makhkamov Yuldashali Mamazhonovich ◽  
◽  
Mirzababayeva Sahiba Mirzaakbarovna ◽  
Keyword(s):  
Experimental Data ◽  
Reinforced Concrete ◽  
High Temperatures ◽  
Calculation Method ◽  
Lateral Force ◽  
New Method ◽  
Design Standards ◽  
Current Design ◽  
Calculation Results ◽  
Concrete Elements

The article presents a new method for calculating bending reinforced concrete elements made of conventional and heat-resistant concrete operating under conditions of high and high technological temperatures on the action of transverse forces. The advantage of the proposed calculation method over the method adopted in the current design standards based on a comparison of the calculation results of the experimental data is shown.

On The Role of a Non-Newtonian Fluid in Short Bearing Theory

1985 ◽  
Vol 107 (1) ◽  
pp. 68-74 ◽  
Author(s):  
R. H. Buckholz
Keyword(s):  
Newtonian Fluid ◽  
Power Law ◽  
Asymptotic Expansions ◽  
Reynolds Equation ◽  
Slenderness Ratio ◽  
Fluid Film ◽  
Matched Asymptotic Expansions ◽  
Film Pressure ◽  
Boundary Shape ◽  
Pressure Distributions

The importance of rheological properties of lubricants has arisen from the realization that non-Newtonian fluid effects are manifested over a broad range of lubrication applications. In this paper a theoretical investigation of short journal bearings performance characteristics for non-Newtonian power-law lubricants is given. A modified form of the Reynolds’ equation for hydrodynamic lubrication is studied in the asymptotic limit of small slenderness ratio (i.e., bearing length to diameter, L/D = λ→0). Fluid film pressure distributions in short bearings of arbitrary azimuthal length are studied using matched asymptotic expansions in the slenderness ratio. The merit of the short bearing approach used in solving a modified Reynolds’ equation by the method of matched asymptotic expansions is emphasized. Fluid film pressure distributions are determined without recourse to numerical solutions to a modified Reynolds’ equation. Power-law rheological exponents less than and equal to one are considered; power-law fluids exhibit reduced load capacities relative to the Newtonian fluid. The cavitation boundary shape is determined from Reynolds’ free surface condition; and the boundary shape is shown to be independent of the bearing eccentricity ratio.

Refined thermal calculation of the locomotive heat engine collector

2020 ◽  
pp. 56-58
Author(s):  
P.V. Gubarev ◽  
D.V. Glazunov ◽  
V.G. Ruban ◽  
A.S. Shapshal
Keyword(s):  
Experimental Data ◽  
Electric Motor ◽  
Heat Balance ◽  
Thermal Imaging ◽  
Heat Engine ◽  
Thermal Calculation ◽  
Calculation Results ◽  
Cooling Air ◽  
The Heat Balance ◽  
Traction Electric Motor

The thermal calculation of the locomotive traction engine collector is proposed. The equations of the heat balance of its elements are obtained taking into account the cooling air. The calculation results and experimental data of thermal imaging control are presented. Keywords: traction electric motor, collector, thermal calculation, thermal imaging control. [email protected]

Tests on Mechanical Properties and Anti-Penetration Performance of Steel-Fiber Reactive Powder Concrete

2013 ◽  
Vol 671-674 ◽  
pp. 1761-1765
Author(s):  
Yong Liu ◽  
Chun Ming Song ◽  
Song Lin Yue
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Compressive Strength ◽  
Reinforced Concrete ◽  
Steel Fiber ◽  
Reactive Powder Concrete ◽  
Calculation Results ◽  
Reactive Powder ◽  
Penetration Tests

In order to get mechanical properties ,some RPC samples with 5% steel fiber are tested, many groups data were obtained such as compressive strength, shear strength and fracture toughness. And a group of tests on RPC with 5% steel-fiber under penetration were also conducted to validate the performance to impact. The penetration tests are carried out by the semi-AP projectiles with the diameter of 57 mm and earth penetrators with the diameter of 80 mm, and velocities of the two kinds of projectiles are 300～600 m/s and 800～900 m/s, respectively. By contrast between the experimental data and the calculation results of C30 reinforced concrete by using experiential formula under penetration, it shows that the resistance of steel-fiber RPC to penetration is 3 times as that of general C30 reinforced concrete.

Optimization of a Specimen Size for the Determination of the Diffusible Hydrogen Content in Metals

2014 ◽  
Vol 698 ◽  
pp. 466-471
Author(s):  
Oleg V. Panchenko ◽  
Alexey M. Levchenko ◽  
Victor A. Karkhin
Keyword(s):  
Hydrogen Content ◽  
Calculation Method ◽  
Specimen Size ◽  
Experimental Results ◽  
Diffusible Hydrogen ◽  
Measuring Methods ◽  
Deposited Metal ◽  
Calculation Results

Specimens of various sizes are used to determine hydrogen content in deposited metals in such standards as ISO 3690, AWS A 4.3, and GOST 23338 while measuring methods are the same. It causes problems in comparison of experimental results and brings up the following question: what kind of specimen size is optimal to determine hydrogen content? An optimal specimen size was estimated using a calculation method. Experimental and calculation results obtained by using specimens with estimated dimensions were compared to the results obtained by using the specimen with dimensions of 100*25*8 mm to determine hydrogen content in a deposited metal.

Numerical Analysis of Dry Gas Face Seals With Spiral Groove and Inner Annular Groove

2008 ◽  
Author(s):  
Xu-Dong Peng ◽  
Li-Li Tan ◽  
Ji-Yun Li ◽  
Song-En Sheng ◽  
Shao-Xian Bai
Keyword(s):  
Reynolds Equation ◽  
Geometric Parameters ◽  
Axial Stiffness ◽  
Face Seal ◽  
Optimization Principle ◽  
Face Seals ◽  
The Face ◽  
Gas Face Seal ◽  
Film Stiffness ◽  
Spiral Grooves

A two-dimensional Reynolds equation was established for isothermal compressible gas between the two faces of a dry gas face seal with both spiral grooves and an inner annular groove onto the hard face. The opening force, the leakage rate, the axial film stiffness and the film stiffness to leakage ratio were calculated by finite element method. The comparisons with the sealing performances of a typical gas face seal only with spiral grooves onto its hard face were made. The effects of the face geometric parameters on the static behavior of such a seal were analyzed. The optimization principle for geometric parameters of a dry gas face seals with spiral grooves and an inner annular groove was presented. The recommended geometric parameters of spiral grooves and circular groove presented by optimization can ensure larger axial stiffness while lower leakage rates.

Two Dimensional Modified Reynolds Equation Including Pressure Dependent Viscosity Effect

2012 ◽  
Author(s):  
Jung Gu Lee ◽  
Alan Palazzolo
Keyword(s):  
Reynolds Equation ◽  
Elastohydrodynamic Lubrication ◽  
Fluid Film ◽  
Maximum Pressure ◽  
Elastic Solids ◽  
Pressure Distributions ◽  
Pressure Dependent Viscosity ◽  
Modified Reynolds Equation ◽  
Dependent Viscosity ◽  
Modified Equation

The Reynolds equation plays an important role for predicting pressure distributions for fluid film bearing analysis, One of the assumptions on the Reynolds equation is that the viscosity is independent of pressure. This assumption is still valid for most fluid film bearing applications, in which the maximum pressure is less than 1 GPa. However, in elastohydrodynamic lubrication (EHL) where the lubricant is subjected to extremely high pressure, this assumption should be reconsidered. The 2D modified Reynolds equation is derived in this study including pressure-dependent viscosity, The solutions of 2D modified Reynolds equation is compared with that of the classical Reynolds equation for the ball bearing case (elastic solids). The pressure distribution obtained from modified equation is slightly higher pressures than the classical Reynolds equations.

scholarly journals Kinetics study on non-isothermal thermochemical liquefaction of corncobs in ethanol-water solution: Effect of ethanol concentration

2018 ◽  
Vol 197 ◽  
pp. 09005
Author(s):  
Bregas Siswahjono Tatag Sembodo ◽  
Hary Sulistyo ◽  
Wahyudi Budi Sediawan ◽  
Mohammad Fahrurrozi
Keyword(s):  
Experimental Data ◽  
Kinetic Models ◽  
Ethanol Concentration ◽  
Water Solution ◽  
Reaction Products ◽  
Gaseous Products ◽  
Bio Oil ◽  
Volatile Products ◽  
Calculation Results ◽  
Oil Gas

Corncobs are potentially processed into bio-oil through thermochemical liquefaction processes. It is difficult to construct kinetics models based on the compounds involved in the reaction. It would be made four kinetic models based on four reaction products, i.e., solids, bio-oil, gas and volatile products. The purposes of the study were to seek kinetics model of thermochemical liquefaction of corncobs in ethanol-water solution and to study the effect of ethanol concentration. The experiment of liquefaction processes of corncobs in ethanol-water solution using sodium carbonate catalyst was performed in the 150 ml autoclave equipped with a magnetic stirrer in the temperature up to 280°C. Four kinetic models were applied to predict the yield of four reaction product lumps. The calculation results were compared to the experimental data. Compared to the others, model 4 was the most realistic and closely matching to the experimental data. In model 4 the reaction mechanism was assumed that biomass (corncobs) first decomposed into bio-oil, followed by decomposition of bio-oil into volatile products reversibly and, finally, volatile products decomposed into gaseous products. The yield of bio-oil increased from 42.05% to 54.93% by increasing to ethanol concentration of 0% to 40%.

A Study on the Simplified Calculation Method for the Residual Ultimate Strength of Damaged Hull Structures

2016 ◽  
Author(s):  
Kimihiro Toh ◽  
Shunsuke Maeda ◽  
Takao Yoshikawa
Keyword(s):  
Ultimate Strength ◽  
Calculation Method ◽  
Fe Analysis ◽  
Structural Members ◽  
Average Strain ◽  
Non Linear ◽  
Compressive Loads ◽  
Calculation Results ◽  
Simplified Calculation ◽  
Simplified Calculation Method

In order to obtain the non-linear average stress-average strain relationships (σ-ε curves) of damaged structural members under both tensile and compressive loads, the systematical calculations are performed using the non-linear FE analysis (FEA) code, LS-DYNA, and the idealized σ-ε curves of damaged structural members are estimated from FEA results. In addition, by introducing the idealized σ-ε curves of damaged structural members to the simplified calculation program, which is developed by authors and based on the Smith’s method, the residual ultimate strength of damaged hull structures is calculated. The residual ultimate strength of damaged hull structures is also calculated utilizing FEA, the calculation results by the simplified calculation program are compared with the results obtained from FE analyses so as to examine the accuracy of simplified calculation method.

scholarly journals USE OF THE MONTE CARLO SERPENT CODE FOR MODELING THE SECOND SERIES OF EXPERIMENTAL DATA OF KUCA SUBCRITICAL INSTALLATION

2019 ◽  
pp. 88-93
Author(s):  
O.R. Trofymenko ◽  
А.V. Nosovsky ◽  
V.I. Gulik
Keyword(s):  
Experimental Data ◽  
Monte Carlo ◽  
Physical Characteristics ◽  
Experimental Results ◽  
Calculation Results ◽  
Effective Multiplication

Modeling of the neutron-physical characteristics of the Kyoto University KUCA subcritical facility was conducted using the Monte Carlo Serpent code. The effective multiplication factors for the critical experiments of the series II on the KUCA research subcritical facility were calculated. The presented calculation results were compared with the experimental results and the results of the calculations made using the Monte Carlo codes MCNP6 and KENO-VI.

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