CALCULATION OF ELLIPSE CIRCUMFERENCE AS A CYLINDRICAL SECTION

In this article, ellipse is studied as cylindrical section and a simple formula is presented to calculate the circumference of an ellipse approximately. 2000 Mathematics Subject Classification: 51N25

COMBINED EXTRUSION OF GLASSES WITH A CONICAL BOTTOM. KINEMATIC AND STRESS STATES OF A CYLINDRICAL PLASTIC REGION LOCATED UNDER THE FORMING GLASS WALL

For extrusion of glasses with a conical bottom using the method of plastic flow by A. L. Vorontsov, the kinematic and stress states of the extruded metal in the area of the plastic deformation center located under the formed wall of the glass and adjacent to the cylindrical section of the matrix were determined. The resulting formulas will be used to determine the stress state in the areas of the focus located under the punch end.

Development of 25N oxygen-kerosene thruster

The paper introduces the scientific and technical groundwork obtained by the author and used as a basis for the development of an oxygen-kerosene rocket engine with a thrust of 25 N. This groundwork represents the results of research carried out on an experimental chamber developed by the author. The design of the chamber made it possible to study the effect of the configuration of the mixing element on its characteristics, the number of holes of oxygen supply to the internal cooling curtain, the length of the cylindrical section behind the curtain belt. The results of tests of various variants of the chamber and their analysis are presented. The results of tests of the developed engine, in which one of the camera variants is implemented, are given as well.

Karakteristik Hydrocyclone untuk Pemisahan Minyak dan Air

Eksplorasi minyak bumi dari sumur-sumur yang sudah tua menghasilkan minyak dengan kandungan air tinggi. Hydrocyclone suatu alat yang berfungsi untuk pemisahan cair-cair berdasarkan perbedaan berat jenis setiap komponen. Pemisahan ini terjadi dikarenanakan adanya gaya sentrifugal dan gaya gravitasi yang dihasilkan dari bentuk hydrocyclone yang seperti kerucut. Perancangan dan pembuatan hydrocyclone menghasilkan alat dengan spesifikasi sebagai berikut : diameter pipa masukan : 25,4 mm, diameter cylindrical section : 120 mm, tinggi cylindrical section : 120 mm, tinggi cone section : 600 mm, diameter pipa overflow : 25,4 mm, diameter pipa underflow : 25,4 mm. Laju alir optimum untuk pemisahan air-minyak tanah pada hydrocyclone adalah 91,8 liter/menit dengan kadar minyak tanah di overflow sebesar 11,4% dan kadar minyak tanah di underflow sebesar 3%.Petroleum exploration from old wells produces oil with a very high water content. Hydrocyclone is a device that functions for liquid-liquid separation based on differences in specific gravity of each component. This separation occurs due to the presence of centrifugal forces and gravitational forces resulting from cone-like forms of hydrocyclone. The design and manufacture of hydrocyclone produces tools with the following specifications: input pipe diameter: 25.4 mm, cylindrical section diameter: 120 mm, high cylindrical section: 120 mm, cone section height: 600 mm, overflow pipe diameter: 25.4 mm, underflow pipe diameter: 25.4 mm. The optimum flow rate for the separation of water-kerosene on hydrocyclone is 91.8 liters / minute with the level of kerosene in overflow of 11.4% and the level of kerosene in underflow of 3%.

Influence of Geometrical Parameters and Reynolds Number on Flat Plate Film Cooling Effectiveness

In the present paper the influence of geometrical deviations, related to the manufacturing process or to a different hole positioning over the vane surface, and of coolant Reynolds number on flat plate film cooling through shaped holes are experimentally investigated. Hole geometrical parameters, such as the length of the cylindrical section, hole injection angle, lateral and forward expansion angles were varied and tested for blowing ratio M values between 1.0 and 2.0, also changing the coolant Reynolds number. The dual-luminophore Pressure Sensitive Paint (PSP) technique was used for measuring the adiabatic film cooling effectiveness distribution. Compared with the standard geometry, the V-shaped hole was shown to produce a better thermal protection, especially in the near hole region. Effectiveness is strongly affected by relatively small changes in the hole geometry, like the length of the cylindrical section and the forward expansion angle. A critical coolant Reynolds number was also identified, whose value changes depending on the hole geometry.

Study on particle movement characteristics in sandblast cylinder based on PIV technology

PIV technology was used to investigate the influence of the particles’ relevant parameters on the instantaneous movement characteristics in the sandblast cylinder under the circumstance of different particle sizes, different section heights and different stacking conditions. As the diameter increased, particles had a greater velocity and energy when approaching the wall, which would cause a serious abrasion. The influence of test selection factors on the particles’ radial velocity of particles was greater than that on axial velocity. The radial velocity and axial velocity on the surface of the cylindrical section were all reduced to a lower level when the particles approach the tank wall. When r > 0.3 R, the particle velocity maintained at a higher level, but then decreased slowly when r > 0.7 R. Therefore, the abrasion of the conical section of the sandblast cylinder when r > 0.3 R should be paid more attention to.

Geometry optimization, factors screening, and introduce a predicting mathematical model of inhalation exposure chamber’s performance.

Background Optimizing the geometry of an inhalation exposure chamber (IEC) results in a uniform and stable distribution of the test atmosphere and enables the modeling of its performance. This study was conducted for the first time to optimize and model the performance of an IEC.Methods The current study was performed on the initial design of the ASRA chamber and to optimize and model it. The matrix of experiments was determined by the design expert software (DE7). The mean of particle concentration (MPC) in the respiratory zone of animals as the response variable, and height of the cylindrical section of the chamber, carrier gas density, inlet concentration, and particle aerodynamic diameter ( da ) as independent variables were considered. Experiments were performed by numerical simulation using ANSYS Workbench package. Particle concentration sampling was measured in 40 points at the opening of each holder in CFD-Post software. To determine the optimal range of the chamber's height, the different of MPC among the holders’ opening was investigated by the ANOVA test. The final mathematical model was achieved by analyzing the response variables in DE7.Results Thirty designs in five geometries with different heights were introduced as the matrix of experiments by DE7. The optimal height was obtained 2-2.5 times the radial of the cylindrical section. Analysis of the results suggested a linear model (2FI) with coefficients of recognition higher than 99%. The final model was significant with the presence of the inlet concentration and da . Gas density and height had no significant effect and were removed ( P >0.05).Conclusion The optimization of the geometry of the ASRA chamber resulted in a uniform and stable distribution of the particles and provided an accurate mathematical model to predict the particle concentration in the target zone.