Vortex Chamber Research Articles

3D Numerical Simulation and Performance Analysis of CO2 Vortex Tubes

In view of the extensive application of swirl flow pipes (vortex tubes) in refrigeration systems, the parameters of swirl flow pipes were investigated to provide optimal cooling and heating conditions. Three-dimensional numerical simulations were carried out using available experimental data and models. The analysis verified that the heat pipe with a length of 175 mm performed better than the swirl flow pipe with a length of 125 mm, confirming experiments by Agrawal. Meanwhile, by comparing different pressures, it was found that in the single-nozzle swirl flow pipe, the greater the increase of pressure (0.1–1.0 MPa), the greater the burden on the vortex chamber and the more serious the wear is, which can be seen in the higher inlet pressure. In order to improve the durability of the swirl flow pipe, we suggest using a swirl flow pipe with more nozzles. Finally, according to the simulation results, with the rise of carbon dioxide pressure potential energy at the inlet, the cooling effect of the swirl flow is first increasing and then decreasing. When the swirl flow pipe is used as a refrigeration device to determine the minimum cooling temperature under the maximum pressure, the lowest temperature of the 125 mm swirl flow pipe was 252.4 K at 0.8 MPa, while the lowest temperature of the 175 mm swirl flow pipe was 246.0 K. Secondly, the distance from the inlet to the hot outlet of the swirl flow pipe had little effect on the cooling temperature and radial velocity, but increasing its distance increased the wall temperature of the swirl flow pipe because it increases the contact time between the airflow and the hot end of the tube wall. When the swirl flow pipe is used as a heat-producing device, increasing the tube length of the swirl flow pipe appropriately increases its maximum heat-producing temperature.

Intensifying Mass and Heat Transfer using a High-g Stator-Rotor Vortex Chamber

Vortex reactors take advantage of the synergy between enhanced heat and mass transfer rates and multifunctional phenomena at different temporal and spatial scales. Proof-of-concept experiments with our novel and innovative STAtor-Rotor VOrtex Chamber (STARVOC) confirm its advantageous features for the sustainable production of chemicals and fuels. STARVOC is a high-g contactor that uses carrier flow (gas or liquid) tangential injection to drive a rotor attached to low-friction bearings. The vortex chamber inside the rotor contains a secondary phase or phases, such as a solids bed, a liquid layer, or a suspension. Carrier fluid passes through the perforated rotor wall and contacts a densely and uniformly distributed secondary phase with enhanced slip velocities. Experiments focused on pressure profiles, rotor angular velocity, and solids azimuthal velocity. With air as the carrier fluid and different solid particle beds as the secondary phase, STARVOC reached bed azimuthal velocities up to four-fold compared to those reached in Gas-Solid Vortex Units with fully static geometry. These results show its potential to improve interfacial heat and mass transfer rates and take advantage of flow energy and angular momentum. Due to its process intensification capabilities, STARVOC is a promising alternative for the state-of-the-art chemical industry.

Numerical investigation of a novel multistage swirl cooling conception in blade leading edge of gas turbine

Swirl cooling is one of the latest and promising internal cooling strategies, which has been widely reported in the designs of the turbine blade leading edges. Based on the traditional single-stage swirl cooling configuration, this paper introduces a novel conception of multistage swirl cooling configuration (two and three stage), aiming to improve the cooling performances of the leading edges without increasing the cooling air consumption. In the new multistage configurations, the vortex chamber is divided into several stages, so that the tangential velocity of cooling air is significantly increased. To reveal the heat transfer and flow characteristics of cooling air in the multistage swirl cooling configuration, a series of numerical simulations are conducted by conjugate heat transfer algorithm under the realistic conditions of gas turbine operations and the real leading edge model of a VKI turbine blade. The numerical results indicate that: under the same coolant mass flow rate, the averaged Nusselt number in the three-stage swirl cooling structure is at least over 75% higher than that in the single-stage structure, and the Nusselt number distribution is also more uniform. At ReD = 40,000, the surface temperature averaged over the entire leading edge wall of the three-stage swirl cooling structure can be nearly 100 K lower than that in the single-stage one. The significant heat transfer enhancement of multistage swirl cooling is at the cost of a higher total pressure loss. However, if the bends connecting the adjacent stages are modified into round-shaped, the pressure loss can be significantly decreased, therefore the thermal performances of the multistage swirl cooling models are higher than that of the single-stage model.

FEATURES OF MODELING THE TRACTION OF MOVEMENT OF MATERIAL PARTICLES IN A VORTICAL LAYER

In the given article the actual modern scientific problem is solved — on the basis of experimental data the mathematical model of movement of a particle in a vortex layer at heat treatment taking into account multiphase of a stream is created.
 At the current level of development of vortex devices, the relevance of research aimed at in-depth study of processes, improvement of structures and manufacturing technology of individual components has increased. The lack of a strict theory is felt most acutely in the design of systems and installations in which the vortex apparatus is one of the main units. In this regard, the priority remains the development of a theory that allows to obtain a fairly reliable mathematical description of the processes occurring in the vortex chamber of the apparatus.
 The patterns of propagation of the swirling jet depend on a large number of different conditions (design features of the nozzle, the intensity of the twist) and flow parameters (their density and speed). The flow in the jet has a complex non-automodal character, in connection with which in other works it was considered expedient to use for calculation numerical methods of integration of equations of motion to describe the non-automodal flow in ordinary jets.
 The disadvantage of these models is that when solving the model of vortex flows go into the model of laminar flows. In this case, many quantities cannot be determined analytically or experimentally. When dividing the flow into the zone of the vortex and the zone of the main vortex, the error in the calculations of the hydrodynamics of the flow, and especially the particles, increases significantly due to the use of different equations of the turbulent viscosity, which is taken for each zone constant. These models are written for a continuous medium and are therefore not suitable for multiphase flow.
 The peculiarities of the trajectory of the material particle in the vortex apparatus are determined and the dependences are obtained, which allow to control the heat treatment time and on the basis of which it is possible to design the optimal vortex device for drying dispersed materials. The mathematical models obtained in this work can be used in methods of calculations and design of vortex heat and mass transfer devices.
 The calculations performed according to the equations of the proposed model show satisfactory agreement with the experimental data. When estimating the relative velocities of the particle in the unloading part of the vortex apparatus, it is obvious that the use of equations for laminar flow, which are traditionally used in calculations, leads to significant errors.

Effects of nozzle inlet size and curvature on the flow development in a bidirectional vortex chamber

A finite-volume solver is used to describe the cyclonic motion in a cylindrical vortex chamber comprising eight tangential injectors and a variable nozzle size. The simulations are performed under steady, incompressible, and inviscid flow conditions with air as the working fluid. First, we apply a fine tetrahedral mesh to minimize cell skewness, particularly near injectors. Second, this mesh is converted into a polyhedral grid to improve convergence characteristics and precision. After achieving convergence, the velocity components are evaluated and compared to existing analytical solutions. We find that well-resolved numerical simulations can accurately predict the expected forced vortex behavior in the core region as well as the free vortex tail in the outer region. We also confirm that the swirl velocity remains axially invariant irrespective of the outlet radius. Similarly, we are able to ascertain that the axial and radial velocities embody the bidirectional nature of the motion. As for the computed pressure distribution, it is found to agree quite well with both theoretical formulations and experimental measurements of cyclone separators. Then using a parametric trade study, the effect of nozzle variations on the internal flow character, mantle structure, and recirculation zones is systematically investigated. Apart from the exit diameter, we find that the nozzle length and inlet curvature can substantially affect the internal flow development including the formation of backflow regions, recirculation zones, and mantle excursions. Finally, an empirical relation is constructed for the nozzle radius of curvature and shown to effectively suppress the emergence of recirculation and backflow regions.

Numerical Simulation of the Effect of Different Numbers of Inlet Nozzles on Vortex Tubes

In order to broaden the application of vortex tubes (VOTU) in industry and to improve the efficiency of cooling and heating, numerical simulations of vortex tubes were carried out. In this study, the temperature, velocity, and pressure fields of three VOTUs with inlet nozzles of 2, 3, and 6 were investigated at different inlet pressures based on previous experimental data and by three-dimensional numerical simulation. It was found that the increase of inlet pressure leads to the increase of energy separation between the hot and cold ends of the three VOTUs. As the number of inlets increases, the pressure difference between the tube wall and the core region gradually strengthens. In contrast, the pressure in the tube center is not affected by the inlet pressure. The number of nozzles affects the inlet and outlet temperatures of the VOTU. When the number of nozzles is 3, and the inlet pressure is 0.6 MPa, the VOTU shows the maximum hot and cold outlet temperature difference of 66 K. The maximum velocity of VOTU appears at the connection of the inlet and vortex chamber, so the inlet is tangential to VOTU, which is beneficial to reduce the loss of gas energy. The wall thickness of the inlet increases gradually to avoid the high-speed gas flow on the erosion of the wall surface. This study has profound guidance for the one-dimensional design of VOTUs.

Study the particle loss from vortex chamber fluidized bed with different conditions

Vortex chamber fluidized bed (VCFB) is a novel type of fluidized bed which has many advantages compare to conventional fluidized beds due to its high-G operation. Hence, the VCFB can replace the conventional fluidized bed for process intensification. However, particle loss at the initial stage of particle injection from VCFB is an important issue which may prevent the particle bed formation inside the VCFB. Therefore, the quality of the fluidized bed will largely depends upon it. The present work aims to study the particle loss from a VCFB at the beginning of particle injection by varying different conditions such as particle feeding location, number of feeding points and particle diameter. A three-dimensional computational fluid dynamics (CFD) model of the VCFB is developed and the particle loss is studied numerically. It is observed that particle loss is minimal when particles are injected from the rear wall of the vortex chamber. Particle loss increases with increasing the number of particle injection points and particle diameter.

Experimental study of the temperature distribution and water evaporation in an axial dual-zone vortex chamber spray dryer

The use of an axial dual-zone vortex chamber for spray drying applications is experimentally studied, focusing on water spray evaporation. In the hot zone of the vortex chamber, hot air (maximum 300 °C) is fed; in the cold zone, mild temperature (80 °C) air. The spray nozzle is installed in the hot feed air zone, in the cylindrical wall of the vortex chamber and injects the water radially toward the center line of the chamber. In spray drying applications, the generated flow and temperature field should allow a fast initial drying of the droplets in the hot zone, followed by rapid evacuation of the particles that are formed to the cold zone where final drying takes place and particles can be evacuated. A slightly different design of the hot and cold zone vortex chambers aims at intensifying the axial motion. Experiments with detailed temperature measurements during dry operation and with injection of a water spray are combined to gain insight in the spray penetration and deflection, the motion of the hot and cold air in the vortex chamber and the resulting temperature profile, and water evaporation and its effect on the temperature profile. A two-fluid nozzle is used and the influence of the hot air inlet temperature, the air flow rate, the water flow rate and the droplet size studied, as well on the temperature profile as on the evaporation capacity. The experimental data allow a first evaluation of the concept.

A Model of Polydisperse Vapor–Droplet Mixture Flow in a Vortex Chamber

A Model of Polydisperse Vapor–Droplet Mixture Flow in a Vortex Chamber

Analysis of vortex cooling fluid-structure interaction under different vortex chamber curvature

The vortex cooling with cascade channel and blade leading edge solid region is established. The flow and heat transfer properties of vortex cooling region, and the stress and displacement properties of blade solid region are analyzed by the fluid-structure interaction method. The ellipses edges with vertical axis to horizontal axis ratio a/b of 0.48, 0.72, 1.00, 1.31 and 1.73 are utilized to form the vortex chamber with different curvature. Influences of vortex chamber curvature on the vortex cooling fluid-structure interaction characteristics are researched to reveal the vortex cooling high heat transfer mechanism deeply. Results show that, for a/b decreasing from 1.73 to 0.48, the overall average Nusselt number and comprehensive heat transfer factor will first increase and then decrease, and the drag coefficient will gradually decrease. As a/b decreases, the high Nusselt number region moves from the target wall next to the nozzle to the target wall under the nozzle and at the vortex chamber bottom. With decreasing a/b, the thermal stress and thermal displacement on the blade pressure surface gradually decrease, while on the blade suction surface the thermal stress first decreases and then increases, and the thermal displacement first increases, then decreases and finally increases. In this study, compared with a/b = 1.73, the heat transfer performance for a/b = 0.72 has been enhanced by 21.00% and can provide the best protection for the blade.

Study of the vortex chamber and its application for the development of novel measurement and control devices

Abstract Based on studies of the flow structure in a short cylindrical vortex chamber, the dependence of the flow rate coefficient on its geometric parameters is proposed. It is shown that the liquid flow form in the chamber’s axial vortex the pressure on which surface is corresponds to the pressure of the outflow cavity. These results are used to measure pressure in high-temperature cavities, using a sleeve with a diameter equal to or slightly larger than the diameter of the axial vortex. The sleeve is installed in the vortex chamber, and connects the pressure on its surface to the pressure sensor. The possibility of using a vortex chamber as a damper of pressure fluctuations has been substantiated. The design of the vortex damper and its tests results are presented; these show the possibility of increasing the stabilization time of the outlet pressure more than three-fold. Variants of regulating devices with a vortex chamber, functioning without changing the flow cross-sections, are proposed and the results of their tests are presented. This is achieved either by introducing an obstacle into the chamber cavity or by displacing the axis of the outlet nozzle position.

A Nonpremixed Annular Jet Vortex Chamber Reactor for Methane Pyrolysis under Oxygen-Enriched Conditions

A novel high-swirl reactor ANJEVOC-CP (annular jet vortex chamber for combustion pyrolysis) was designed for producing high-value chemicals such as alkynes and olefins from natural gas. In such a s...

Numerical Simulations of Cryogenic Hydrogen Cooling in Vortex Tubes with Smooth Transitions

Improving efficiency of hydrogen cooling in cryogenic conditions is important for the wider applications of hydrogen energy systems. The approach investigated in this study is based on a Ranque-Hilsch vortex tube (RHVT) that generates temperature separation in a working fluid. The simplicity of RHVT is also a valuable characteristic for cryogenic systems. In the present work, novel shapes of RHVT are computationally investigated with the goal to raise efficiency of the cooling process. Specifically, a smooth transition is arranged between a vortex chamber, where compressed gas is injected, and the main tube with two exit ports at the tube ends. Flow simulations have been carried out using STAR-CCM+ software with the real-gas Redlich-Kwong model for hydrogen at temperatures near 70 K. It is determined that a vortex tube with a smooth transition of moderate size manifests about 7% improvement of the cooling efficiency when compared vortex tubes that use traditional vortex chambers with stepped transitions and a no-chamber setup with direct gas injection.

Flow fields of a non-Newtonian fluid in vortex chamber pumps

Problem. Pumping different fluids by hydraulic transport is associated with fast wear of the pump contact surfaces. The fluids being pumped are often non-Newtonian. The use of jet pumps for pumping is impractical due to low efficiency. Vortex chamber pumps may have higher efficiency when pumping non-Newtonian fluids, however, their operation on such fluids has not yet been studied. The aim of this work is to study the characteristics of the flow fields of a non-Newtonian fluid using the example of a Bingham fluid in the vortex chamber pump. Methodology. Predicting pump energy performance and determining flow fields for highly viscous fluids using CFD simulations enables advanced jet pumps to handle non-Newtonian fluids. Results. Modeling was carried out based on the numerical solution of the RANS equations with the SST turbulence model. To ensure the operability of the vortex chamber pump when pumping non-Newtonian fluid, with known rheological parameters of the mixture, it is necessary to select the required supply pressure for the active flow, and also to consider the issue of diluting the liquid with water to reduce the mixture viscosity and achieve the specified values of the pumping energy parameters. Originality. The hypothesis that the vortex chamber supercharger can operate on a hypothetical ideal fluid has been confirmed. In this case, the performance indicators of such a supercharger improve and tend to ideal. With an increase in plastic viscosity, the volumetric flow rate of the pumped fluid decreases, and at high values of the viscosity, an active flow is ejected through the axial channels. Practical value. Researchers can use the theoretical results of this work to design new devices for pumping other Bingham fluids, such as oil paint, resins, varnishes, swamp soils, and many others.

Investigation of the process of shredding coniferous sawdust in a crusher with a two-way material supply system

Russia is one of the main countries in the extraction and processing of forest resources. Waste from wood processing is still one of the cheapest energy sources. Therefore Russia is actively developing and introducing technologies for processing waste from the forest industry. The technology for producing fuel pellets and briquettes is widespread. One of the operations of this technology is the preliminary grinding of the feedstock. Nowadays, traditional hammer mills are used for this, which are used in the feed industry. As a result of the analysis of the designs of such crushers, it was revealed that when grinding materials with a low specific gravity, their potential is not fully utilized. A hypothesis has been put forward that an increase in the productivity of hammer crushers when grinding materials with a low specific gravity is possible due to a change in the conditions for introducing raw materials. To test this hypothesis, a crusher with two feed necks and a vortex chamber was developed. Research has been carried out to study the influence of the conditions for entering the shredded material into the crushing chamber. The performance of the crusher is determined with three ways of feeding the shredded material.

Numerical Study toward Optimization of Spray Drying in a Novel Radial Multizone Dryer

In this paper, an intensified spray-drying process in a novel Radial Multizone Dryer (RMD) is analyzed by means of CFD. A three-dimensional Eulerian–Lagrangian multiphase model is applied to investigate the effect of solids outlet location, relative hot/cold airflow ratio, and droplet size on heat and mass transfer characteristics, G-acceleration, residence time, and separation efficiency of the product. The results indicate that the temperature pattern in the dryer is dependent on the solids outlet location. A stable, symmetric spray behavior with maximum evaporation in the hot zone is observed when the solids outlet is placed at the periphery of the vortex chamber. The maximum product separation efficiency (85 wt %) is obtained by applying high G-acceleration (at relative hot/cold ratio of 0.75) and narrow droplet size distribution (45–70 µm). The separation of different sized particles with distinct drying times is also observed. Smaller particles (<32 µm) leave the reactor via the gas outlet, while the majority of big particles leave it via the solids outlet, thus depicting in situ particle separation. The results revealed the feasibility and benefits of a multizone drying operation and that the RMD can be an attractive solution for spray drying technology.

A Review on Analysis of Heat Transfer Coefficient in Internal Rib Tube

The rate of heat transfer is increased by a fin arrangement applied to the rectangular duct. In order to save energy, many industrial heat exchange devices use various techniques to improve heat transfer, such as: B. fins, dimples, vortex chamber and ribbed tabs. The most common technique used to improve heat transfer is to add fins to the flow channel. The ribs are of simple construction and are widely used in many industries. Turbulent kinetic energy generation increases turbulent heat transfer in the duct due to flow disturbances caused by fin arrangements. The shape of the fin plays an important role in improving heat transfer as it affects the formation of bubble separation behind the fin and the amount of turbulent kinetic energy generated.

Research the Influence of Hydraulic Model on Vibration of Pump

In this paper, the cooling water pump of centrifugal equipment is taken as the research object in ship system. The pump set is normally open. And, it is also one of the main vibration sources of ship. On the premise of meeting the requirement of hydraulic performance parameters, several different hydraulic model prototypes of this pump set are manufactured. On the same test bench, the vibration tests of this pump show that the measured values are quite different. Fluid software is used to analyse these hydraulic models under the same boundary conditions. It is found that there are obvious differences in hydraulic fluctuations and fluid vortices among impeller passage, vortex chamber, inlet and outlet passages. In order to verify the inference, vibration test and analysis are carried out on the whole pump set and the foots of installation. The corresponding relationship was found out between the fluid fluctuation of hydraulic components and the vibration characteristics. Based on the corresponding relationship, the current hydraulic model of pump is optimized and improved. The parameters of hydraulic model which can affect the vibration sensitivity of pump are optimized. Finally, the experimental results prove that this method can reduce the vibration effectively.

A novel slit-less gas-solid vortex reactor dryer: Experimental validation and scale-up

A slit-less gas-solid vortex reactor (SL-RFBSG) has high heat and mass transfer capability, applicable in pharmaceutical and food processing industries, especially in food grain drying and preservation. Validating the numerical outcomes with experimental results of the SL-GSVR vortex chamber with a capacity of 500 g, the scale-up of this reactor is performed numerically to a solid capacity of 3000 g. In the present investigation, a three-dimensional computational fluid dynamics analysis of gas-solid hydrodynamics and heat transfer characteristics in SL-GSVR has been performed using the commercial software ANSYS FLUENT 14.5, applying an Eulerian-Eulerian approach for the gas-solid phase. As the SL-GSVR vortex chamber is developed without slits, it improves bed-uniformity and fluidization, along with the reduction in system cost and complexity. Comparing numerical outcomes with experimental results, the measured temperature difference, inventory, heat transfer coefficient in the radial direction and transverse directions are 0.24%, 7.72%, 14.8%, and 17.8%, respectively. The requirement of drying air in the SL-GSVR dryer is decreased by 18.6%, with an improvement in the product quality compared to the RFB reactor. Further, the solid loading capacity of the scaled-up SL-GSVR drying chamber has been increased to 3000 g.

Optimal design of vortex chamber pump

The difficult operating conditions during the pumping of abrasive solid mediums lead to the rapid wear of the mechanical parts of the pumps. The use of jet pumps can significantly increase the reliability and durability of pumping equipment. However, direct-flow jet pumps have low efficiency. The use of the centrifugal force led to the creation of new jet pumps - vortex chamber pumps. Their performance indicators are better than direct-flow jet pump ones. The geometric parameters of the flow channel of the vortex chamber pumps were optimized. The study was carried out experimentally and numerically. Numerical simulation is based on solving the RANS equations with the shear stress transport turbulence model. The geometrical dimensions of the vortex chamber pump with the best performance indicators such as pressure and flow are found. The maximum achievable operating parameters of the vortex chamber pump are analyzed. The comparison of simulation results with experimental data is made.