Vortex Chamber Research Articles

CFD analysis of helical nozzles effects on the energy separation in a vortex tube

In this article computational fluid dynamics (CFD) analysis of a three-dimensional steady state compressible and turbulent flow has been carried out through a vortex tube. The numerical models use the k-? turbulence model to simulate an axisymmetric computational domain along with periodic boundary conditions. The present research has focused on the energy separation and flow field behavior of a vortex tube by utilizing both straight and helical nozzles. Three kinds of nozzles set include of 3 and 6 straight and 3 helical nozzles have been investigated and their principal effects as cold temperature difference was compared. The studied vortex tubes dimensions are kept the same for all models. The numerical values of hot and cold outlet temperature differences indicate the considerable operating role of helical nozzles, even a few numbers of that in comparing with straight nozzles. The results showed that this type of nozzles causes to form higher swirl velocity in the vortex chamber than the straight one. To be presented numerical results in this paper are validated by both available experimental data and flow characteristics such as stagnation point situation and the location of maximum wall temperature as two important facts. These comparisons showed reasonable agreement.

The Numerical Investigation on Vortex Flow Behavior Using FLOW-3D

In this paper a numerical investigation is given for a Rankine type vortex flow inside the cylindrical vortex chamber using FLOW-3D. The FLOW-3D is a general purpose computational fluid dynamics (CFD) package. The fluid motion is described with non-linear, transient, second-order differential equations. Additionally the free surface also exists in many simulations carried out with FLOW-3D because flow parameters and materials properties, such as density, velocity and pressure experience a discontinuity at it. After analysis of the vortex by mentioned details, the finding of time-averaged velocity components, turbulent components, turbulence dissipation, in the 2D briefed sections of chamber were depicted. It was found that there are different flow patterns like clockwise/anticlockwise vortices and some sink points combined with each other in different time intervals, decaying and generating along the time. Also the turbulence intensity and dissipations around the boundary conditions of chamber like central flushing discharge are higher than the flow body. It was also found that this CFD package was not able to simulate thoroughly the central air core of chamber after filling of chamber. This analysis is validated by comparison with previous experimental data that was measured in vortex settling basin.

Experimental Study of Integrated Vortex Board with Exergy Analyses

The integrated vortex board was made up of many vortex chambers, it was the integration managed in individual vortex tube and its structure was more complicated. It could be regard as one and open ones mouth the system to study. In this paper, basing on the first and second law of thermodynamics, thermodynamics model was set up firstly , which was suitable for the exergy analyses of integrated vortex board energy separation, then the relationships of exergy efficiency and irreversibility were obtained. Combining with the experiment data , the exergy of the integrated vortex board was analyzed, in view of the effect of inlet pressure, cold mass, diameter of outlet orifice, length of hot tube, structure of entrance nozzle on energy separation effect and exergy efficiency. The dimension and operating condition of integrated vortex board could be optimized.

Cooling of return water from industrial plants in vortex chambers

A vortex chamber with an atomizing device is proposed for cooling of return water from industrial plants, and the effect of design and production parameters are theoretically investigated.

STATIC PERFORMANCE CHARACTERISTICS OF VORTEX RATE SENSOR

The vortex rate sensor is a fluidic gyroscope with no moving parts and can be used in very difficultconditions like radiation, high temperature and noise with minimum cost of manufacturing andmaintenance. A vortex rate sensor made of wood has been designed and manufactured to studytheoretically and experimentally its static performance .A rig has been built to carry out the study,the test carried out with three different air flow rates (100, 150, and 200 l/min).The results show thatthe relation between the differential pressure taken from the sensor pickoff points and the angularvelocity of the sensor was linear.The present work involved theoretical and experimental study ofvortex rate sensor static characteristics .Vortex rate sensor has been designed and manufacturedwith dimensions-:Radius of vortex chamber= 140 mm, Radius of sink tube rs= 4.5 mm, the pickoff hole diameter =2mm, Height of vortex chamber b= 19 mm, Height of pickoff pipe h= 25 mm.

Influence of inlet conditions on vortex characteristics

Vortex chambers are normally used for arc stabilization in linear plasma torches. In the present work, the effect of uniformity of the gas inlet channel distribution on the stabilizing characteristics of a swirled flow is studied numerically. The formation of a complex flow pattern with a toroidal recirculating flow area inside the vortex chamber is observed. For some regimes, two local maxima of the tangential velocity are observed in the middle section of the chamber. It is shown that an increment of the number of gas inlet channels leads to a more uniform gas input with disappearance of the second maximum, which increases the velocity amplification coefficient and, correspondingly, results in a better stabilizing effect. The obtained profiles of the radial distribution of the tangential velocity are compared with the results of Oseen’s equation for an unconfined vortex.

Detonation of a coal-air mixture with addition of hydrogen in plane-radial vortex chambers

Results of an experimental study of continuous and pulsed detonation of a coal-air mixture with addition of hydrogen in plane-radial vortex chambers 204 and 500 mm in diameter are presented. The tested substance is pulverized activated charcoal. A method of coal powder supply through narrow channels by means of adding the gas at the injector entrance is found. Stable regimes of continuous spin detonation with one or two transverse detonation waves moving with velocities of 1.8–1.6 km/sec are obtained for the first time in the combustor 204 mm in diameter. The frequency of pulsed detonation with radial waves is 4–4.8 kHz. The limits of continuous detonation in the combustor 500 mm in diameter are extended: regimes of continuous spin detonation with a large number (5–8) of transverse waves moving with velocities of 1.8–1.5 km/sec are obtained, the amount of hydrogen added to coal is reduced to 2.8%, and combustion of coarser fuel particles is ensured owing to an increased residence time of the mixture in the combustor. The wave structure and the flow in the vicinity of the waves are reconstructed in the combustor plane.

Investigation of structure of single-phase vortex flows

The design of the vortex chamber, which is a cylinder with a partially cut wall was developed. Several such chambers may be contained in the device. One of the structural elements of the device is rotated at a given speed. An intensity of the arisen vortex depends on the relative speed of a couple chamber-agitator, and the opening angle of the vortex chamber. Investigation of the structure of vortex flows is to determine profiles of peripheral and axial velocities in the vortex chambers. Studies have revealed the presence of self-oscillations in the investigated flows. Rational values of the opening angle of the vortex chamber that ensure maximum peripheral speed should be selected from a range of 60–100°.

New lumped fuel manufacturing processes

The results of studies aimed to extend the application area of Kansk-Achinsk brown coal by its preliminary thermal upgrading via flash heating in generation next drying units (vortex chambers) are reported.

Discharge coefficient for bottom orifice of vortex chamber

This research presents investigations on the discharge coefficient of a circular orifice located at the apex of an inverted conical hopper attached to the bottom of a cylindrical vortex chamber. A circular jet inflow tangentially enters the vortex chamber at the top periphery of the conical hopper. Different sizes of orifices and inflow jet discharges were applied in the experiments to investigate the variation of the discharge coefficient. The effect of overflow at the upper outlet on the discharge coefficient was also investigated. Based on the test data, empirical relations for the discharge coefficient are proposed. It is found that in the presence of tangential jet inflow, the discharge coefficient is considerably smaller than that without tangential jet inflow and the presence of overflow significantly reduces it.

Explosion-free flash drying of coal in a vortex flow of heat-transfer gas

The process of rapid nonexplosive drying of coals in cyclone-type devices has been considered. The principles of calculation of a vortex chamber, the characteristics of thermally treated coal, and the main promising lines in the vortex drying of coals are discussed.

Investigation of a fluidized bed in a vortex chamber

Results on the tangential velocity in a fluidized bed measured by a laser Doppler velocimeter and by a mechanical propeller are presented. The reasons for the difference in the bed rotation velocities obtained by these measurement techniques are analyzed on the basis of numerical calculations of the multiphase flow dynamics.

Dynamic Response of Rocket Swirl Injectors, Part II: Nonlinear Dynamic Response

of a classic swirl (simplex) injector. The abrupt convergence resonance model (ACRM) describes the magnitude of injector mass flow response assuming a radial step contraction, while the conical convergence resonance model (CCRM) treats the contraction from the vortex chamber to the nozzle using an arbitrary number of small radial steps. In this second part of the study, numerical calculations are performed to assess nonlinear dynamic response and to compare results with ACRM and CCRM predictions. The vehicle for these computations is a boundary element method (BEM) that preserves surface shapes with high accuracy.

In Vitro Comparison of Lung Delivery of Xopenex and Flovent HFA Using Vortex and AeroChamber Plus Holding Chambers

PURPOSE: This in vitro study reports estimates of lung delivery of the two asthma medications Xopenex HFA and Flovent HFA delivered via Vortex and AeroChamber holding chambers. Such information is useful in guiding clincians’ choice of a holding chamber for a specific MDI.

An investigation of the mechanism of acoustic vibrations in swirl flows

An experimental setup is developed and systematic measurements are performed of pressure fields and amplitude-frequency characteristics of acoustic vibrations generated by impact swirl flows. A stable effect is revealed of generation of resonance acoustic vibrations under conditions of efflux of impact swirl jets. Curves are given of distribution of pressure on the obstacle surface for different values of the width of gap between the obstacle surface and the vortex chamber. The emergence of acoustic resonance with a frequency dependent on gas flow rate is registered for a certain correlation between the geometric parameters of the region of efflux of impact swirl air jet. An approximate analytical solution based on the use of a physical model of acoustic flow is obtained for theoretical description of the observed phenomenon of acoustic resonance in an impact swirl jet.

Benchmark and parametric study of a passive flow controller (fluidic device) for the development of optimal designs using a CFD code

A passive flow controller or a fluidic device (FD) is used for a safety injection system (SIS) for efficient use of nuclear reactor emergency cooling water since it can control the injection flow rate in a passive and optimal way. The performance of the FD is represented by pressure loss coefficient ( K-factor) which is further affected by the configuration of the components such as a control port direction and a nozzle angle. The flow control mechanism that is varied according to the water level inside a vortex chamber determines the duration of the safety injection. This paper deals with a computational fluid dynamics (CFD) analysis for simulating the flow characteristics of the FD using the ANSYS CFX 11.0. The CFD analysis is benchmarked against existing experimental data to obtain applicability to the prediction of the FD performance in terms of K-factor. The CFD calculation is implemented with Shear Stress Transport (SST) model for a swirling flow and a strong streamline curvature in the vortex chamber of the FD, considering a numerical efficiency. Based on the benchmark results, parametric analyses are performed for an optimal design of the FD by varying the control port direction and the nozzle angle. Consequently, the FD performance is enhanced according to the angle of the control port nozzle.

Experimental Investigation of a Vortex-Flow Restrictor: Rain-Blocker Performance Tests

Flow restrictors, or rain blockers, are commonly used at inlets of storm-drain networks to limit the peak flow entering storm sewers. This reduces the likelihood of the sewer system becoming hydraulically overloaded, thus preventing sewer backups and residential flooding. The vortex-flow restrictor limits flow by forcing flow through a helicoidal chamber followed by sudden expansions and contractions that create high levels of turbulence. The high turbulence produced in a vortex-flow restrictor limits flow rates much more than a simple orifice, while maintaining a relatively large flow opening that can reduce the chances of clogging. Hydraulic tests were conducted with a vortex-flow restrictor (FR Type I) as well as a modified version in which the vortex chamber was removed (FR Type II), in which case the restrictor works a simple orifice plate. Discharge coefficients were calculated for the tested flow restrictor configurations and were compared to the case in which no flow restrictor was in place.

Theoretical and Experimental Study of the Dynamics of a Liquid Swirl Injector

DOI: 10.2514/1.44271 The purpose of this paper is to summarize important aspects of the dynamic characteristic of an open-end swirl injector used in a liquid rocket engine. Theoretical analysis about the dynamic characteristics of open-end swirl injectors has been performed, considering the influence of the axial velocity of liquid in the vortex chamber on the volume flux pulsation. Moreover, the model of interaction between the tangential channel and the vortex chamber has also been modified by taking into account the influence of reflected waves; the formula for the transfer functions of the open-end swirl injectors has been deduced. The dynamics of the open-end swirl injector have been calculated. Toinvestigatethedynamiccharacteristicsoftheswirlinjectorexperimentally,aninner flow-pulsationmeasurement method has been developed according to the characteristics of the liquid flow in the swirl injector. The principle of measuringtheinstantaneousvolume flowusingconductancemethodisdiscussed.Thesensoriscomposedofalock-in amplifyingcircuitandanelectronicprobe,fabricatedfromporoustitaniummaterial;anexperimentalmeasurement oftheopen-endswirlinjectorisconductedusingthissensor.Theexperimentalresultshowsthatboththemethodand the sensor can meet the requirement for a flow-pulsation measurement in the swirl injector. This is of considerable significance in the experimental investigation of the swirl injector dynamic characteristics and liquid rocket engine unstable combustion.

Investigation of Near-Wall Turbulent Flows in a Vortex Chamber

Investigation of Near-Wall Turbulent Flows in a Vortex Chamber

Sidewall Boundary Layers of the Bidirectional Vortex

This study seeks to resolve the sidewall boundary layers forming in the axial and radial directions of a bidirectional vortex chamber. Our analysis is initiated by the formulation of the laminar boundary-layer equations via an order of magnitude reduction of the incompressible Navier-Stokes equations at the wall. Asymptotic theory is then applied to linearize and systematically truncate the governing equations, thus converting them from partial differential equations to more manageable ordinary differential equations. Scaling transformations are additionally applied to resolve the rapid changes arising near the sidewall. Because of the spatial character of the outer solutions, further transformations of the dependent variables are undertaken to secure the axially changing outer conditions. Through the use of matched-asymptotic expansions, we recover similar boundary-layer structures in all three orthogonal directions: the axial and radial components presented here, and the wall-tangential boundary layer obtained previously. This behavior is consistent with the resultant velocity being dominated by its tangential component and with the tangential boundary layer being axially invariant. These factors cause the axial layer to remain uniform in the streamwise direction. Based on the ensuing asymptotic results, viscous corrections at the wall are seen to be mainly dependent on the vortex Reynolds number, V. The latter combines the swirl number, the Reynolds number, and the chamber aspect ratio. Having obtained the three components of the velocity, essential flow characteristics, such as pressure, vorticity, swirling intensity, and wall shear stresses, are evaluated and discussed.