scholarly journals Uniformity of working processes of jet and vortex ejectors, vortex tube and Hartmann–Sprenger pipe

Author(s):  
V. I. Kuznetsov ◽  
◽  
V. V. Makarov ◽  

Based on the previously considered physical and mathematical models of jet and vortex ejectors, vortex tube and Hartmann–Sprenger tube, it makes a conclusion about the identity of the processes of exchange of work and heat in these devices. The influence of viscosity, tangential stresses, and the gradient of linear and angular velocities on the transfer of kinetic energy from a high-pressure to a low-pressure gas is shown. The difference of thermodynamic temperatures for heat exchange of high-pressure and low-pressure gases is taken into account.

Author(s):  
Yuriy Alyushin

An exact solution is obtained for the kinetic energy in the general case of the spatial motion of solids with arbitrary rotation, which differs from the Koenig formula by three additional terms with centrifugal moments of inertia. The description of motion in the Lagrange form and the superposition principle are used, which provides a geometric summation of the velocities and accelerations of the joint motions in the Lagrange form for any particle at any time. The integrand function in the equation for kinetic energy is represented by the sum of the identical velocity components of the joint plane-parallel motions. The moments of inertia in the Koenig formula do not change during movement and can be calculated from the current or initial state of the body. The centrifugal moments change and turn to 0 when rotating relative to the main central axes only for bodies with equal main moments of inertia, for example, for a ball. In other cases, the difference in the main moments of inertia leads to cyclic changes in the kinetic energy with the possible manifestation of precession and nutation, the amplitude of which depends on the angular velocities of rotation of the body. An example of using equations for a robot with one helical and two rotational kinematic pairs is given.


1987 ◽  
Vol 50 (1) ◽  
pp. 28-37 ◽  
Author(s):  
RUTH BANDLER ◽  
PARIS M. BRICKEY ◽  
STANLEY M. CICHOWICZ ◽  
JOHN S. GECAN ◽  
PHILIP B. MISLIVEC

Two studies were done to determine the effects of processing equipment on Howard mold and rot fragment counts of tomato catsup. In a pilot plant study in 1980, batches of catsup with known cut-out rot levels were produced and processed through various types of comminution equipment. Urschel and Fitzpatrick mills and homogenizers at 500 to 700 and 1500 to 2000 psi increased mold counts more than twofold over the range of data obtained. Contrary to previous reports, Urschel mills increased rot counts significantly. A nationwide survey was conducted in 1983 to determine if similar effects would be found with well-characterized commercial products. Data were obtained on inline and finished products from 164 lots of catsup produced at 16 plants located across the country. Urschel and Fitzpatrick mills tended to increase mold counts over twofold and caused a slight increase in rot counts. High pressure homogenizers (≥2000 psi) tended to decrease mold counts; low pressure homogenizers (<2000 psi) increased them. Homogenization at any pressure reduced rot counts dramatically. Although mold counts were highest for catsup produced in the eastern United States and lowest for catsup produced in the West, milling and low pressure homogenization were also most prevalent in the East and least prevalent in the West. When the effects of these types of comminution were removed, the difference between regions diminished. Compared with the norm, rainfall levels for the growing regions involved in this survey were fairly typical.


1862 ◽  
Vol 152 ◽  
pp. 579-589 ◽  

In the Second Part of these researches we have given the results of our experiments on the difference between the temperatures of an elastic fluid on the high- and low-pressure sides of a porous plug through which it was transmitted. The gases employed were atmospheric air and carbonic acid. With the former, 0°·0176 of cooling effect was observed for each pound per square inch of difference of pressure, the temperature on the high-pressure side being 17°·25. With the latter gas, 0°·0833 of cooling effect was produced per lb. of difference of pressure, the temperature on the high-pressure side being 12°·844. It was also shown that in each of the above gases the difference of the temperatures on the opposite sides of the porous plug is sensibly proportional to the difference of the pressures.


Author(s):  
Johannes Schedelmaier ◽  
Manfred Po¨lzl

Depending on the plant location for a new project different Codes and Standards are applied for design and calculation of high pressure equipment. Many countries do not have a specific code for high pressure vessels and components, respectively the high pressure used in petrochemical plant is out of the code range. In this case the purchaser or the process licensor determines the code to be applied on the equipment for the new plant. This paper provides a technical analysis and comparison for high pressure components calculated according to the following codes: ASME VIII, AD 2000 and CODAP 95. Design and calculation results according to the different codes are verified on an example of a double pipe heat exchanger using identical mechanical properties of materials and the same operating conditions. The results are illustrated on figures for different low pressure and high pressure components. The literature does not define a limit between low pressure, high pressure and ultra high pressure. As the difference between steam pressure in the jacket (3,3MPa), pressure in the process tube (50 MPa, 160 MPa, 360 MPa) and autofrettage pressure (1000MPa) is very significant, this sequence is applied in the paper. Economic aspects are more and more important for new projects in order to minimize costs for high sophisticated equipment. For this reason also a cost analysis was performed for the calculation examples and the economic impact of application of different codes is indicated on a diagram. The technical–economical evaluation leads to an optimised product.


2009 ◽  
Vol 40 (2) ◽  
pp. 179-186
Author(s):  
V. A. Rassokhin ◽  
S. Yu. Olennikov ◽  
E. A. Chirkova ◽  
A. A. Kondratiev ◽  
Yu. V. Matveev

2020 ◽  
Author(s):  
Ruobin Dai ◽  
Hongyi Han ◽  
Tianlin Wang ◽  
Jiayi Li ◽  
Chuyang Y. Tang ◽  
...  

Commercial polymeric membranes are generally recognized to have low sustainability as membranes need to be replaced and abandoned after reaching the end of their life. At present, only techniques for downcycling end-of-life high-pressure membranes are available. For the first time, this study paves the way for upcycling fouled/end-of-life low-pressure membranes to fabricate new high-pressure membranes for water purification, forming a closed eco-loop of membrane recycling with significantly improved sustainability.


Author(s):  
Leonid S. Bobe ◽  
Nikolay A. Salnikov

Analysis and calculation have been conducted of the process of low-pressure reverse osmosis in the membrane apparatus of the system for recycling hygiene water for the space station. The paper describes the physics of the reverse osmosis treatment and determines the motive force of the process, which is the difference of effective pressures (operating pressure minus osmotic pressure) in the solution near the surface of the membrane and in the purified water. It is demonstrated that the membrane scrubbing action is accompanied by diffusion outflow of the cleaning agent components away from the membrane. The mass transfer coefficient and the difference of concentrations (and, accordingly, the difference of osmotic pressures) in the boundary layer of the pressure channel can be determined using an extended analogy between mass transfer and heat transfer. A procedure has been proposed and proven in an experiment for calculating the throughput of a reverse osmosis apparatus purifying the hygiene water obtained through the use of a cleaning agent used in sanitation and housekeeping procedures on Earth. Key words: life support system, hygiene water, water processing, low-pressure reverse osmosis, space station.


Crystals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 34
Author(s):  
Akun Liang ◽  
Robin Turnbull ◽  
Enrico Bandiello ◽  
Ibraheem Yousef ◽  
Catalin Popescu ◽  
...  

We report the first high-pressure spectroscopy study on Zn(IO3)2 using synchrotron far-infrared radiation. Spectroscopy was conducted up to pressures of 17 GPa at room temperature. Twenty-five phonons were identified below 600 cm−1 for the initial monoclinic low-pressure polymorph of Zn(IO3)2. The pressure response of the modes with wavenumbers above 150 cm−1 has been characterized, with modes exhibiting non-linear responses and frequency discontinuities that have been proposed to be related to the existence of phase transitions. Analysis of the high-pressure spectra acquired on compression indicates that Zn(IO3)2 undergoes subtle phase transitions around 3 and 8 GPa, followed by a more drastic transition around 13 GPa.


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