Swirl Flow Generator Research Articles

Experimental and numerical study on the thermal and hydrodynamic characteristics of non-Newtonian decaying swirl flows

Experimental and numerical investigation has been carried out to determine the effectiveness of three novel inlet swirl flow generators on heat transfer of a non-Newtonian drilling nanofluid under turbulent flow conditions in a constant heat flux heat exchanger. Thermophysical and rheological properties of working fluid were measured and an empirical model for thermal conductivity was proposed. Non-Newtonian temperature dependent power law coefficients for drilling nanofluid were also presented. Experimental Nusselt number and friction factor were evaluated and compared to the numerical model results. Numerical Nusselt number and swirl number were used to predict thermal and hydrodynamic behavior of the flow at different Reynolds numbers from 4000 to 10,000. The outcomes demonstrate that the fluid flow and convective heat transfer are a function of nanofluid concentration, twist angle and Reynolds number. It also has been shown that the hydrodynamic and thermal characteristics of the flow are not necessarily similar in the whole domain.

Research on multi-radial swirling flow for optimal control of dust dispersion and pollution at a fully mechanized tunnelling face

Research on multi-radial swirling flow for optimal control of dust dispersion and pollution at a fully mechanized tunnelling face

Experimental evaluation of a novel swirling flow generator placed in an artery with a stenosis

Experimental evaluation of a novel swirling flow generator placed in an artery with a stenosis

Numerical analysis of a novel gas-liquid pre-separation cyclone

Numerical analysis of a novel gas-liquid pre-separation cyclone

Wavy-tape insert designed for managing highly concentrated solar energy on absorber tube of parabolic trough receiver

Wavy-tape insert designed for managing highly concentrated solar energy on absorber tube of parabolic trough receiver

Investigation into aerodynamic and heat transfer of annular channel with inner and outer surface of the shape truncated cone and swirling fluid flow

We have carried out Investigation into aerodynamic and convective heat transfer of the annular channel. Inner or outer surface of annular channel has shape of blunt-nosed cone tapering to outlet end. Truncated cone connects to a cyclone swirling flow generator. Asymmetric and unsteady flow from the swirling generator in the shape of periodic process gives rise to the formation of secondary flows of the type Taylor-Görtler vortices. These vortices occupy the whole space of the annular channel, with the axes, which coincide with the motion direction of the major stream. Contraction of cross-sectional area of channel (in both cases 52%) causes a marked increase in total velocity of flow, primarily due to its axial component and promotes a more intensive vortex generation. Vortex structures have a significant influence on both average heat transfer and surface distribution. At cross-sections of the annular channel we observe similarity of curves describing distribution of total velocity about wall and heat flux density on the surface. The coordinates of maximum and minimum values of velocity and heat flux coincide. At the average cross-section channel of maximum value of heat transfer is greater than minimum of about by a factor of 2.7 times for outer heat transfer surface and about by a factor of 1.7 times for inner heat transfer surface. Taper channel has a much higher influence on heat transfer of the inner surface than the outer surface and manifests itself at lower values of dimensionless axial coordinate. For the investigated taper cone geometry of the annular channel the heat transfer coefficient of inner surface increases at the outlet section and exceeds value in comparison with straight-line section by 91 … 98%. Heat transfer of the outer cylinder in the same section increases only by 5 … 11%. The increase in average heat transfer over the surfaces is 36% and 4% respectively.

Improvement of separation performance by fluid motion in the membrane module with a helical baffle

Improvement of separation performance by fluid motion in the membrane module with a helical baffle

Experimental Validation and Numerical Analysis of the Swirling Flow in a Submerged Entry Nozzle and Mold by Using a Reverse TurboSwirl in a Billet Continuous Casting Process

As an alternative to some traditional methods to generate a swirling flow in the continuous casting process, the use of a new swirling flow generator, TurboSwirl, is studied. Specifically, a reversed TurboSwirl device is designed as part of a submerged entry nozzle (SEN) for a round billet continuous casting process. Mathematical modeling is used to investigate this new design and a water model experiment is carried out to validate the mathematical model. The predicted velocities by the turbulence models: realizable k–ϵ model, Reynold stress model (RSM), and detached eddy simulation (DES) are compared to the measured results from an ultrasound velocity profile (UVP) method. The DES model can give the best prediction inside the SEN and has a deviation less than 3.1% compared to the measured results. Moreover, based on the validated mathematical model and the new design of the SEN, the effect of the swirling flow generated by the reverse TurboSwirl on the flow field of the SEN and mold is compared to the design of the electromagnetic swirl flow generator (EMSFG). A very strong swirling flow in the SEN and a stable flow pattern in the mold can be obtained by the reverse TurboSwirl compared to the EMSFG.

Optimization of static vanes in a supersonic separator for gas purification

Optimization of static vanes in a supersonic separator for gas purification

Experimental investigation of turbulent heat transfer by counter and co-swirling flow in a flat tube fitted with twin twisted tapes

Experimental investigation of turbulent heat transfer by counter and co-swirling flow in a flat tube fitted with twin twisted tapes

Evaluation of influence of the inlet swirling flow on the flow field in a triple elbow system

Evaluation of influence of the inlet swirling flow on the flow field in a triple elbow system

An Experimental and Numerical Study of Swirling Flow Generated by TurboSwirl in an Uphill Teeming Ingot Casting Process

A swirling flow has been demonstrated to be beneficial for making the flow pattern even and to reduce turbulence during filling in ingot casting. A new swirling flow generation device, TurboSwirl, ...

Heat Transfer Enhancement of Laminar Flow of Ethylene Glycol through a Square Channel Fitted with Angular Cut Wavy Strip

Heat Transfer Enhancement of Laminar Flow of Ethylene Glycol through a Square Channel Fitted with Angular Cut Wavy Strip

Effect of TurboSwirl Structure on an Uphill Teeming Ingot Casting Process

To produce high-quality ingot cast steel with a better surface quality, it would be beneficial for the uphill teeming process if a much more stable flow pattern could be achieved in the runners. Several techniques have been utilized in the industry to try to obtain a stable flow of liquid steel, such as a swirling flow. Some research has indicated that a swirl blade inserted in the horizontal and vertical runners, or some other additional devices and physics could generate a swirling flow in order to give a lower hump height, avoid mold flux entrapment, and improve the quality of the ingot products, and a new swirling flow generation component, TurboSwirl, was introduced to improve the flow pattern. It has recently been demonstrated that the TurboSwirl method can effectively reduce the risk of mold flux entrapment, lower the maximum wall shear stress, and decrease velocity fluctuations. The TurboSwirl is built at the elbow of the runners as a connection between the horizontal and vertical runners. It is located near the mold and it generates a tangential flow that can be used with a divergent nozzle in order to decrease the axial velocity of the vertical flow into the mold. This stabilizes flow before the fluid enters the mold. However, high wall shear stresses develop at the walls due to the fierce rotation in the TurboSwirl. In order to achieve a calmer flow and to protect the refractory wall, some structural improvements have been made. It was found that by changing the flaring angle of the divergent nozzle, it was possible to lower the axial velocity and wall shear stress. Moreover, when the vertical runner and the divergent nozzle were not placed at the center of the TurboSwirl, quite different flow patterns could be obtained to meet to different requirements. In addition, the swirl numbers of all the cases mentioned above were calculated to ensure that the swirling flow was strong enough to generate a swirling flow of the liquid steel in the TurboSwirl.

Inclusion Behavior under a Swirl Flow in a Submerged Entry Nozzle and Mold

Previous studies have verified that a swirl flow generated in a submerged entry nozzle (SEN) can effectively improve a flow pattern and a heat transfer in a continuous casting (CC) process. In order to obtain a further in-depth understanding with respect to the effect of a swirl flow on a CC process, the inclusion behavior in a SEN and a mold was studied in the present work. The flow field and the temperature field of molten steel as well as the inclusion behavior in a SEN and a square bloom mold were simulated under the influence of a rotating electromagnetic field (swirl generator). Also, the influence of different inclusion parameters such as the densities, sizes, and boundary conditions, on the inclusion behavior was studied. The results show that a flow pattern in a SEN can be characterized into three distinct flow regions: an accelerating flow of molten steel from an electromagnetic swirl flow generator (EMSFG) inlet to an EMSFG center, a decelerating flow of molten steel from an EMSFG center to an EMSFG outlet, and a recirculation flow of molten steel from an EMSFG outlet to an SEN outlet. In addition, it was found that light Al2O3 inclusion moves towards the rotational center by a centrifugal force, and that a swirl flow prevents nozzle clogging. Moreover, it was also found that the inclusion separation to a mold meniscus increased and that the inclusions trapped into a solidified shell wall decreased when using a swirl flow.

Design of Magnetic Fields for Half and Full Type Electromagnetic Swirl Flow Generators

In this work, the placement of an electromagnetic swirl flow generator (EMSFG) around a submerged entry nozzle (SEN) was proposed as a method for generating a rotating electromagnetic field in a continuous casting (CC) process of steel. First, two kinds of a full type EMSFG and a half type EMSFG were designed based on mathematical modeling. Then, distributions of magnetic flux intensity in an EMSFG as well as distributions of Lorentz force in molten steel were simulated. It was found that the EMSFG structure and electromagnetic parameters have an important effect on magnetic flux intensity and Lorentz force distributions. For both a full type and a half type EMSFG, the magnetic flux intensity and Lorentz force increases as the magnetomotive force increases. Especially, for a full type EMSFG, the magnetic flux intensity is distributed evenly in molten steel. Moreover, the Lorentz force increases along a radial direction in the molten steel in the SEN. However, for a half type EMSFG, the magnetic flux intensity and Lorentz force decreases gradually towards the region without an EMSFG. Consequently, a full type EMSFG with a 44 000 AT magnetomotive force and a 50 Hz frequency is more suitable to apply in the operation of an EMSFG under actual production conditions.

The Influence of Swirl Flow on the Flow Field, Temperature Field and Inclusion Behavior when Using a Half Type Electromagnetic Swirl Flow Generator in a Submerged Entry and Mold

In the preceding work, the inclusion behavior in a submerged entry nozzle (SEN) and mold induced by using a swirl flow has been investigated. The results showed that a swirl flow can effectively promote the inclusions removal to the meniscus as well as reduce the inclusions entrapment at the solidified shell wall. Moreover, that the swirl flow was generated by using a full type electromagnetic swirl flow generator (EMSFG). In the present work, a kind of a half type EMSFG was investigated, since it is easier to implement in a production scale. The influence of the stirrer on the fluid flow, heat transfer, and inclusion behavior in the SEN and mold was studied. Furthermore, a comparison between these two types of EMSFG from the aspects of flow field, temperature field, and inclusion behavior was done. In addition, the effect of different magnetomotive forces, inclusion sizes, densities as well as boundary conditions on the inclusion behavior was studied. The results show that the effect of a half type EMSFG (88000 AT) on the molten steel is very close to a full type case (44000 AT). More specifically, the flow pattern, temperature distribution as well as inclusion behavior in the SEN and mold look very similar. Also, it was found that from the viewpoints of the inclusions separation to the mold meniscus and the inclusions trapping at the solidified shell wall, better results could be obtained for a “Trap” boundary condition when using half type EMSFGs.

A232 下向き閉塞分岐配管に生じる流動現象に関する研究 : 侵入深さの変動メカニズム(OS2 保全・設備診断技術(5))

Hot water in a main pipe flows into a branch pipe and forms a thermally stratified layer with cold water at a bent section. Fluctuation of the thermally stratified layer may initiates thermal fatigue crack in the branch pipe. It has been reported that the fluctuation of penetration depth induced by the main flow in the branch pipe with a closed end was caused by generation of a large swirl flow at L = 4D_b. Experiments with the rectangular and reduced branch pipes were conducted to suppress the fluctuation of penetration depth induced by the main flow. It was shown that the fluctuation of penetration depth in the rectangular pipe was suppressed, because the large swirl flow at L = 4D_b was not formed. It was also shown that the rectangular and reduced branch pipes were available to decrease the penetration depth by the main flow in the branch pipe.

A Numerical Simulation of the Effects of Swirling Flow on Jet Penetration in a Rotating Channel

The hydrodynamic effects of a jet in a swirling cross-flow problem, which is related to gas turbine blades film cooling, were numerically simulated using large eddy simulation with artificial inflow boundary conditions. The purpose of this study is to investigate the effects of swirling flow on a jet effusing from an inclined hole in a rotating channel. The finite volume method and the unsteady PISO algorithm were applied on a non-uniform staggered grid. The work is naturally divided into two main parts. The first part (the swirl flow generator), is a channel rotates axially to generate a turbulent swirling flow at different values of swirl number (SN) of 0.0, 0.15, 0.3, and 0.5 while the second part (test section), is a channel rotating about a parallel axis to investigate the interaction of a square jet with the turbulent swirling flow, generated by the first part, for the prediction of the film cooling under rotating conditions. Four different values of rotation number (Ro) were applied to the test section. The air jet was injected at 30 deg in the streamwise direction, at a velocity ratio of 1.0 and a jet Reynolds number of 4,700, based on the hole width and the jet exit velocity. It was found that the swirling flows primarily displayed the velocity profile of a forced vortex. Weak reverse flow was observed near the main vortex core, which moved in the direction of the swirl and deformed the kidney shape of the Counter Rotating Vortex Pair. As SN increases (SN > 0), the jet trajectory twists in an increasingly x-axis direction due to the centrifugal force effects of the swirl flow, and shifts from the centreline of the channel to the right-hand side (Z/D =+ 1.5). Also, it was shown that rotation has a strong impact on the mixing behaviour and film cooling effectiveness. Finally, it was concluded that the film cooling decreases rapidly as SN increases.

An experimental study on the decaying swirl flow in a tube

An experimental study on the decaying swirl flow in a tube