Simulations of multi-size solid particles in a modified fluidized bed separator

This study focusses on the description of the internal state of a modified fluidized bed separator also known as the reflux classifier. The device is a highperformance beneficiating technology employed in many mineral and coal processing industries. A 2D continuum model was used to examine the transport behavior of solid particles within the reflux classifier for a multicomponent mixture under continuous operating conditions. Three different types of feeds comprising solid particles of size ranging 49?421 ?m and densities equal to 1400, 2490 and 5000 kg/m3 were simulated simultaneously under identical process conditions. The feed flux and fluidization velocity were kept at 0.0037 m3/m2s and 0.022 m/s, respectively. A comparison of the simulation results showed that the value of separation size shifted towards lower values, 340, 181 and 90 ?m, when the density of the feed was changed from 1400 to 2490 and 5000 kg/m3, respectively. The data generated through simulations was used to demonstrate the movement of solid particle within the inclined section by plotting the net flux of the solid particles across the inclined channel width. It was observed that the net flux of finer solid particles was higher than the coarser ones within the inclined section.

Wheel Obstraction Detection with Machine Learning

In this paper, to blessing an ongoing programmed innovative and insightful based absolutely rail assessment framework, which plays examinations at sixteen km/h with a casing rate of 20 fps. The framework identifies significant rail segments including ties, tie plates, and grapples, with high exactness and productivity. To accomplish this objective, to initially widen an immovable of picture and video investigation and after that prompt a particular worldwide streamlining structure to join proof from two or three cameras, Global Positioning System, and separation size apparatus to moreover improve the recognition execution. Additionally, as the grapple is a significant kind of rail clasp, to've as needs be propelled the push to hit upon stay special cases, which consolidates evaluating the grapple circumstances on the tie stage and recognizing grapple design exemptions on the consistence level. Quantitative examination performed on a huge video certainties set caught with unmistakable tune and lighting installations conditions, notwithstanding on a continuous order check, has affirmed empotoring execution on each rail perspective recognition and stay special case location. In particular, a middle of 94.67% accuracy and ninety three% remember expense has been finished for recognizing each of the 3 rail segments, and a 100% recognition charge is practiced for consistence level stay special case with three phony positives predictable with hour. To our excellent comprehension, our framework is the essential to address and clear up both perspective and special case location issues in this rail assessment region

Tamaño de partícula de Pumita y Tezontle en el crecimiento de plantas de Ocimum Basilicum L.

There are few reports about the effect of pumice in the production of basil (Ocimum basilicum L.), an economically significant plant. The size of pumice particles can influence basil production. The objective of this study was to compare the growth and production of basil plants cultivated using pumice and tezontle particles of various sizes. Pumice (jal) and tezontle were mined in Xalisco, Nayarit. Five particle sizes per material were used —size 0 = 0.1≥ ≤12 (material without particle separation); size 1 = 7.5 ≥ ≤12; size 2 = 5.0≥ <7.5; size 3 = 3.0≥ <5.0; size 4 = 0.8≥ <3.0; size 5 = 0.1≥ <0.8— and their physical properties were determined. The basil was transplanted into pots which had been filled with particles of each size. The following variables from the above-ground part of the plants were evaluated: plant height, stem diameter, and leaves, stem, inflorescence, and total dry mass; root variables were also evaluated. Size-4 particles recorded the highest values for height, stem diameter, and total dry biomass; this result was attributed to physical properties. The highest value was obtained for every variable aboveground when pumice substrate was used.

Separation mitigation using pressure feedback technique for hypersonic shock wave boundary layer interaction

Present studies are focused on the use of pressure feedback technique as a separation control technique for ramp induced flow separation at hypersonic speed. Numerical simulations portrayed that though pressure feedback technique can reduce the flow separation, further cooling of the feedback channel enhances its potential for separation control. Marginal cooling of channel walls to 175 K has reduced separation bubble size by 18.18% while strong cooling of those walls to 50 K reduced the separation by 30%. Such low enthalpy perfect gas simulations also showed the lower effectiveness of pressure feedback technique with increased ramp angle. Further, it has been noticed from the perfect and nonequilibrium gas flow simulations that the cooling of pressure feedback channel introduces differential separation size for the same wall-to-total temperature ratio cases. Integration of cooled pressure feedback channel with blunt leading edge configuration showed reduced separation size for any bluntness radius. Effectiveness of this integration is seen in lowering the values of inversion and equivalent radii. Thus, use of cooled pressure feedback technique in conjunction with leading edge bluntness is not only seen to have reduced the intensity of shock wave boundary layer interaction but also has enhanced the controllability of blunted leading edge without altering the entropy layer–boundary layer interaction.

Stokes Number Analysis of the Moving Droplets in the Steam-Water Separator

The steam-water separator is vitally important equipment to remove the droplets entrained by the vapor stream to provide dry saturated steam for the steam turbine in the nuclear power station. With the development of the large nuclear power station and the vessel nuclear power plant, the steam-water separation performance should be more efficient under the condition of higher pressure, power load and circulating ratio. The droplet motion model, which is solved by typical four steps Runge-Kutta method and validated against the experimental results, is developed according to the physical phenomenon description and the mechanism comprehension of the vapor entrained droplets moving in the wave-type vanes separator. The Euler-Lagrange methodology is adopted to simulate the moving droplet entrained by the vapor stream in the wave-type vanes separator and the separation performance is investigated. The separation efficiency of the separator and motion trajectories of droplets with various sizes are presented. Stokes Number (St) of diverse droplets is obtained to analyze the influence of Stokes Number on the moving droplets trajectories and the separation efficiency. The results reveal that the values of Stokes Number for most of the moving droplets in the wave-type vanes separator are beyond 1, which indicates that most of droplets are likely to collide with the solid wall of the separator. Only when the droplet velocity is smaller than 1 m/s or the droplet radius is less than 2 μm, the Stokes Number may be below 1 and the moving droplets can be entrained by the stream flow until escaping from the separator. The analysis can forecast the maximum critical separation size of the droplets that cannot be removed, and the minimum critical separation size of the droplets that can be removed throughly by the separator and guide the design of the separator.

Improved compressor corner separation prediction using the quadratic constitutive relation

This work presents the implementation and study of the quadratic constitutive relation nonlinear eddy-viscosity model with representative compressor application, for which the corner separation has been poorly predicted with the widely used linear Boussinesq eddy-viscosity model. With the introduction of the Reynolds stress anisotropy, the secondary flow of the second kind and its effect on the corner flow can be well captured and this results in greatly improved prediction of pressure coefficient, total pressure loss coefficient and the corner separation size. Without the quadratic constitutive relation model, the separation size and loss are generally over-estimated. The mechanism of the improvement is studied using both the vortex dynamics and the momentum equation. It is proved that quadratic constitutive relation model consumes low CPU time and provides much improved compressor corner separation prediction without worsening the convergence property.

Design of Compressor Endwall Velocity Triangles

The operating range of a compressor is usually limited by the rapid growth of three-dimensional (3D) separations in the endwall flow region. In contrast, the freestream region is not usually close to its diffusion limit and has little effect on overall range. In light of these two distinct flow regions, this paper considers how velocity triangles in the endwall region should be designed to give a more balanced spanwise failure across the span of a blade row. In the first part of this paper, the sensitivity of 3D separations in a single blade row to variations in realistic multistage inlet conditions and endwall geometry is investigated. It is shown that a blade's 3D separation size is largely controlled by the dynamic pressure within the incoming endwall “repeating stage” boundary layer and not the detailed local geometry within the blade row. In the second part of this paper, the traditional design process is “flipped.” Instead of redesigning a blade's endwall geometry to cope with a particular inlet profile into the blade row, the endwall region is redesigned in the multistage environment to “tailor” the inlet profile into downstream blade rows, giving the designer a new extra degree-of-freedom. This extra degree-of-freedom is exploited to balance freestream and endwall operating range, resulting in a compressor having an increased operating range of ∼20%. If this increased operating range is traded with reduced blade count, it is shown that a design efficiency improvement of ∼0.5% can be unlocked.

Study on the Classification Performance of Vibration Lamella Thickener

This paper mainly describes the relation between the overflow quantity, separation size, classification efficiency and Reynolds number under the stable stage of vibration lamella thickener. Using a device with one tilting-narrow flow classification element, experiments on classification of pure quartz slurry have been carried out.we can conclude that the overflow quantity is proportional to the separation and classification is best under the condition of turbulent flow.