Swirl Device Research Articles

Cement slurry penetration behavior of swirl grouting technology

Traditional pressure grouting technology operates under steady pressure conditions, causing the grout to easily flow along preferential pathways. This results in uneven grout penetration and increased economic costs. This study proposes swirl grouting technology, which effectively improves this problem. To verify the effectiveness of swirl grouting, a fan-shaped blade tool was also proposed. The grout penetration performance was investigated through experimental studies. The length, width, height, weight, and uniformity of the grouted bodies produced by the swirl grouting method were compared with those produced by the steady pressure grouting method. Then, the mechanisms of swirl grouting were analyzed through transparent disc visualization experiments. The results demonstrated that, at different water–cement ratios, the swirl device increased the penetration length in the X, Y, and Z directions by 43.3%, 27.8%, and 45.8%, respectively, compared to the conventional straight device, and by 57.3%, 39.4%, and 55.6%, respectively, compared to the fan blade device. Moreover, the swirl device increased the weight of the grouted stone body by 54.9% compared to the conventional straight device and by 91.0% compared to the fan blade device, significantly enhancing filling efficiency. The uniformity coefficient of the swirl device permeation decreased by 56.6% and 51.0%, respectively, compared to the conventional straight device and the fan blade device, resulting in a more uniform grout distribution. The transparent disc visualization experiment further revealed the advantage of the swirl device in promoting the migration of fine particles, with a significant increase in average penetration distance and a penetration shape closer to a regular circle. The rotating flow path of the swirl device imparts additional rotational momentum and multidirectional penetration capabilities. The resulting turbulence accelerates the mixing of grout with the soil matrix, facilitating the migration of fine particles, expanding flow channels, and reducing flow resistance. This combination of effects enhances penetration efficiency and reduces energy loss. This study offers significant practical application value for improving engineering quality, construction efficiency, and reducing costs.

Effect of electric field on separation characteristics of oil–water–solid three phases separating device

Lubricating oil can decay as a result of the mixing of water with solid impurities in the working process, and this process can adversely affect the performance of the machinery. Therefore, desolidification and dewatering are key steps in overall oil purification. In general, a basic swirl device cannot sustain efficient dewatering and desolidification. Thus, a three-phase separating device enhanced by an electric field has been proposed. To study the performance of the oil-water-solid separation process, a numerical model of the device was conceived based on combining the governing equations of the flow field and the electric field with the particle-tracking equation giving due consideration to the population balance model. The tangential velocity and the distribution of solid particles at various voltage amplitudes were analyzed, and the effect of the electric field on the oil, water and particle separation process was studied. The results show that at 3 kV, the tangential velocity increased by 5.06%, compared with that at 12 kV. Application of an electric field to the device was found to accelerate more solid particles which assembled near the wall of the device, and where the number of the particles near the axial plane decreased. The maximum particle concentration near the wall at the z = 630 mm plane is 20.24%. Moreover, the average residence time of the solid particles initially exhibited an increasing and then a decreasing trend. Additionally, the increase in the droplet size and enhancement of the oil-water separation process are promoted through the action of the electric field. The rate for desolidification, deoiling and dewatering at 3 kV are 93.60%, 93.30% and 95.59%, respectively.

Biomimetic swirl device and hydrogen enrichment effects on LPG fueled engine

Inspired by the humpback-whale flipper which enables robust aerodynamic force production, we propose a biomimetic blade design for small Biomimetic Swirl Device (BSD) added on gaseous engine inlet system. Such system can achieve robustness in aerodynamic performance for the intake flow. Therefore, the BSD design has an important impact on swirl generation inside the engine cylinder which its geometry was defined by a wavelength, leading edge radius and amplitude. For this reason, a numerical analysis method, by means a computational fluid dynamics 3D modeling technique, was utilized to study the in-cylinder flow characteristics investigating the optimal BSD geometry. Moreover, the effect of Hydrogen on in-cylinder flow characteristics of liquefied petroleum gas (LPG) bi-fuel engine has been examined using the BSD. In this research, five designs of the BSD with the dimensionless amplitude A* varied at 0.08, 0.12, 0.16, 0.2 and 0.24 were compared with the model without BSD to investigate its effect on the air-LPG flow inside the combustion chamber. The results showed that the BSD with A* = 0.2 created more turbulence, in-cylinder velocity, swirl in the combustion chamber than the other designs. Simulation results indicated also that LPG-30% H2 blend with BSD added gives the optimal in-cylinder flow characteristics of the TKE, the velocity and the swirl ratio.

Investigation of newly designed Alternate Perforated V-Notch (APVN) twisted tape with heat transfer characteristics

Swirl device is seen as a path to enhance the efficiency of a thermal switch. Swirl device with fabricated form of porosity and v-cuts twisted tape (tt) inner pipe insert helps to augment performance by improving the heat transfer (U) coefficient. This work is related to the thermal performance factor (TPF), friction factor (ff) and Nusselt (NNu) number in the inner tube inserted with a innovative design of Alternate Perforated V-Notch (APVN) tape having twisted ratio 6.25 incorporating porosity amount of Rp = 1.087% and width (w/W) ratio = 0.333, were investigated features to improve heat transfer rate. Enhancement in turbulent generation of the primary flow into the secondary flow with this design. Experiment test was performed on a pipe in pipe tubes of (d) internal diameter of 0.013 m with test section length of 0.9 m. Temperature of the warm water had kept constant at 60 °C within the Reynolds number range of 2246–16,224. The heat exchanger with empty tube (without tt) and the input of normal twisted tape (tt) has been checked. In addition to the investigated range, NNu, ff and TPF in the tube with APVN twisted tape insertion were observed (Rp - ratio) 1.833–2.276, 2.155–4.549 and 1.84–1.778 times more than the values of empty tube. The presented work is very useful in the field of energy conservation through maximum transfer of heat in the industrial process.

Influence of structure on the combustion characteristics of a small aero-gas turbine engine combustor

In this paper, a combustor using vortex plates instead of swirler as the head swirl device has been studied. The flow and combustion characteristics in the combustor mainly depend on the combustor structural characteristics, therefore, the study of combustor structural parameters on combustion characteristics is a key means for the improvement of combustor performance. Numerical simulation method was used to study the flow and combustion characteristics in the primary combustion zone of a small aero-gas turbine engine annular reverse-flow combustor. The results show that the nozzle mounted on the flame tube outer wall is better than on the head considering the benefit to fuel/air mixing and combustion performance for this type combustor. The cooperation between vortex plates and primary combustion holes is the method of organizing flow in the primary combustion zone, and the cooperation is effective than simply relying on the vortex plates or the primary combustion holes. The circumferential flame propagation mainly relies on the vortex plates according the results. The number of vortex plates has effect on the shape of the combustor head reverse-flow zone, and there is an optimal value to optimize the combustion performance.

Supersonic separation technology for carbon dioxide and hydrogen sulfide removal from natural gas

Abstract A cleaner approach was proposed for removing CO2 and H2S from highly acid natural gas by supersonic separation technology. For this purpose, different structures of Laval nozzles and supersonic swirling separation devices were designed. The mathematical models of gas flow in the nozzle were established, and the supersonic flow characteristics of CH4–H2S–CO2 ternary mixture were accurately predicted by adding the real gas state equation and the transport equation to describe the rotational and irrotational flow field. The effects of nozzle structure, swirl angle of static vanes and inlet parameters on the refrigeration performance of the nozzle and the separation characteristics of the swirl device were systematically investigated. The results show that the average temperature at the nozzle outlet can be as low as 135.2 K under the condition of inlet temperature 293.15 K, inlet pressure 4 MPa and 20 mol % acid gas. It indicates that the refrigeration effect produced by high speed expansion of acid natural gas in the supersonic nozzle can provide a favorable liquefying environment for the acid components, which confirms the feasibility of capturing acid components by supersonic separation device. Better refrigeration performance can be achieved in the nozzle with higher outlet Mach number, but the pressure recovery capacity of the device will be suppressed accordingly. As swirl angle increases from 73.90° to 81.79°, the maximum tangential velocity in the nozzle rises from 119.6 m/s to 212.5 m/s, the separation performance of the swirl device increases, while the pressure and temperature at the same location decrease slightly. However, the increase of swirl intensity will restrict the flow capacity of the separator. For the given supersonic swirling separation device, it shows a good adaptability in separation performance when changing the inlet parameters.

On the highly swirling flow through a confined bluff-body

We address highly swirling, confined-bluff-body-flow evolving through a burner; particularly, contributions of the swirling motion to a central-recirculation-zone (CRZ) downstream the injector. Previous studies suggest that flame stability reduces in combustors lacking this zone; careful consideration of the CRZ is thus desirable. We use Reynolds-Averaged-Navier–Stokes (RANS) and Large-Eddy-Simulation (LES) to simulate the flow, and the influence of the swirl device was included in defining the inflow conditions for LES simulations. We use mean velocity profiles and turbulence statistics to test results. There is qualitative agreement between computed and reported experimental data, and we document quantitative differences obtained with the RANS models. LES velocity field results are mostly within 3% of the experimental data, better than the latest reported LES data, reinforcing the suitability of our approach. We took advantage of the quality of the LES mesh, which solves 95.6% of the resolved-turbulence-energy, to present the vorticity structures showing the precessing vortex motion on the CRZ boundaries. Anisotropic states of the Reynolds-stress were characterized with the aid of an anisotropy invariant map, a novelty for this type of burner; the turbulence states considerably vary inside the burner, behaving isotropically in the center of the CRZ, whereas axisymmetric turbulence is predominant in the other areas of the CRZ. The results reinforce the importance of applying appropriate turbulence models and inflow conditions for simulations involving confined-bluff-body-flows in order to capture the main flow fields and structures in the CRZ.

Experimental and Numerical Study in Horizontal Tube by using Swirl Device

Experimental and Numerical Study in Horizontal Tube by using Swirl Device

Simulation of nanomaterial turbulent modeling in appearance of compound swirl device concerning exergy drop

The present investigation concern with the study on exergy loss and turbulent flow inside a round duct equipped with complex turbulator. The Copper oxide/H2O nanofluid at 0.04 particle volume concentration has been considered as carrier fluid. The tests were examined under the turbulent flow with Reynolds ranges of 5000 < Re < 15000. The duct has been conducted under constant heat flux of wall surface. Outputs indicates that flow blockage increases with augment of Re and b. Exergy drop is reversely proportional to the convective mode and therefore Xd declines with rise of tape width and Re.

Effect of swirl flow on whey protein fouling and cleaning in a straight duct

Whey protein fouling is a complex phenomenon involving several mechanisms. Product, surface properties and process parameters interact simultaneously. This experimental work focuses on the effect of a swirl flow on whey protein fouling and cleaning in a straight tube, independently of any other factors. In a holding section after a heating zone composed of a plate heat exchanger, the dry deposit mass obtained from a straight tube was compared with that obtained in the presence of a swirl flow. For varying conditions, namely two protein concentrations, two processing temperatures and two fouling durations, the dry deposit mass increases despite the wall shear stress increase induced by the swirl device. Nevertheless, the cleaning time was found to be significantly shorter in presence of swirl flow in laminar and turbulent conditions. These results reveal that cleaning efficiency can be improved by such a swirl insert, which is seldom used in the food process industry.

Experimental investigation of in-cylinder air flow to optimize number of helical guide vanes to enhance DI diesel engine performance using mamey sapote biodiesel

The current research work investigates the influence of helical guide vanes in to the intake runner of a D.I diesel engine operating by the high viscous Mamey Sapote biodiesel to enhance in-cylinder suction air flow features. Helical guide vanes of different number of vanes are produced from 3D printing and placed in the intake manifold to examine the air flow characteristics. Four different helical guide vane devices namely 3, 4, 5 and 6 vanes of the same dimensions are tested in a D.I diesel engine operating with Mamey Sapote biodiesel blend. As per the experimental results of engine performance and emission characteristics, it is found that 5 vanes helical guide vane swirl device exhibited in addition number of increased improvements such as the brake power and bake thermal efficiency by 2.4% and 8.63% respectively and the HC, NOx, Carbon monoxide and, Smoke densities are reduced by 15.62%, 4.23%, 14.27% and 9.6% at peak load operating conditions as collate with normal engine at the same load. Hence this investigation concluded that Helical Guide Vane Devices successfully enhanced the in-cylinder air flow to improve better addition of Mamey Sapote biodiesel with air leading in better performance of the engine than without vanes.

Experimental Investigation Of Couple Precessing Vortex Ropes In A Hydraulic Vortex

The work is devoted to the experimental study of the interaction of the precessing vortex pair in the hydrodynamic vortex chamber. Swirling flow was created by a 12 tangentially directed rectangular nozzles. Design swirl number was varied in the range 0÷6.6 based on the geometry of the swirl device. The Reynolds number was varied in the range of 6 000÷52 000. Preliminary visual experiments has been conducted with changing output boundary conditions for controlling parameters of the vortex structure. It was found that stable mode with a double precessing structure is realized at full open outlet. Setting of diaphragm on the outlet of vortex chamber allows us to suppress the precession motion and significantly stabilize the flow. Further experiments included the quantitative measurement of the velocity distributions carried out using a laser Doppler anemometry (LDA).

INVESTIGATION OF GUIDE VANE SWIRL AND TUMBLE DEVICE TO IMPROVE IN-CYLINDER AIR FLOW FOR COMPRESSION IGNITION ENGINE RUNNING WITH BIODIESEL

Biodiesel is expected to become the main alternative fuel for transportation purposes in the coming future as a result of the recession of crude oil. The main advantage that makes biodiesel the first choice as a substitute for petroleum-based fuel is that biodiesel can be used in a compression ignition engine (CI) with minor modification. Unfortunately, with biodiesel, the engine experiences reductions in power and torque, and increases in fuel consumption and carbon deposits inside the combustion chamber mainly due to lower calorific value and heavier molecules present in the biodiesel. One of the solutions to minimize this problem is to increase the in-cylinder air motion and use this to break up the heavier molecules and mix these molecules with air. To achieve this, a high turbulent flow is required inside the cylinder. This paper presents the model of the Guide Vane Swirl and Tumble Device (GVSTD) to develop an organized in-cylinder turbulent flow. The basic model of GVSTD consists of simple fins imposed inside the intake system. Through computer simulations, the results of air flow characteristics are compared with a conventional intake system. The height of GVSTD vanes was varied at 25%, 50% and 75% of the intake runner radius. The results show that in-cylinder velocity, turbulence kinetic energy and absolute pressure at the start of the injection increase around 41%, 6% and 3%, respectively more than the ordinary system which is expected to improve the mixing of biodiesel and air resulting in better combustion.

Numerical Simulation of the Flow in the Fuel Injector in the Sharply Inhomogeneous Electric Field

The results of detailed numerical simulation of the flow in an injector including electrohydro- dynamic interaction in sharply inhomogeneous electric field formed by electrode system closed to the needle-plane type are presented. The aim of the simulation is to estimate the charge rate flow at the fuel injector outlet. The results were obtained using the open-source package OpenFOAM in which the corresponding models of electrohydrodynamics were added. The para- metric calculations were performed for axisymmetric model using RANS k–ω SST turbulence model. Due to swirl device in fuel injector the flow is strongly swirling. To obtain parameters for axisymmetric flow calculations the 3D simulation was performed for the simplified injector model including swirl device and without electrodes.

Optimizations of Vane Height of Guide Vane Swirl and Tumble Device to Improve in Cylinder Airflow Characteristics of a Diesel Engine Running with Vegetable Oil

Generally, compression ignition engine operating on neat vegetable oil and its blend with diesel fuel experience a reduction of engine performance and increase in exhaust emissions due to higher viscosity and lower volatility of vegetable oil than diesel fuel. Vegetable oil is less prone to evaporate, diffuse and mix with the in-cylinder air which eventually reduces the combustion efficiency and produces more emissions of CO and unburned HC. Therefore, this research investigated the potential of guide vane swirl and tumble device (GVSTD) to guide the air entrance to create more organized turbulence inside the fuel injected region to enhance the mixing process of air and vegetable oil. In order to do so, a base model of 3D computational fluid dynamic of internal combustion engine simulation was developed, verified and then simulations were carried with different GVSTD models. The results of turbulent kinetic energy, velocity, vorticity and swirling strength were compared to determine the optimum vane height. This research found that the 2 mm vane height was the optimum vane height with 35° twist angle, four vanes being arranged perpendicularly to each other and 30 mm vane length. Other different heights of vanes also showed improvement but 2 mm height showed the highest number of improvements. This could be due to the airflow pattern in bowl-inpiston head shape was amplified by the airflow pattern produced by the guide vane of 2 mm vane height. The extra turbulence, swirl, vorticity and velocity in the fuel injected region created by the 2 mm height vane is expected to enhance the mixing of vegetable oils with air to improve combustion and reduce CO and unburned HC emissions.

Comparison of the heat transfer performance and friction characteristics between fixed and rotating turbine-type swirl generators fitted in a small circular tube

This paper is a continuation of the authors’ previous work [W. Duangthongsuk, S. Wongwises, An experimental investigation of the heat transfer and pressure drop characteristics of a circular tube fitted with rotating turbine-type swirl generators, Exp. Therm. Fluid Sci. 45, (2013), 8–15.]. Swirl generators inserted into a conventional smooth tube is an innovative way to increase the thermal performance of the heat exchangers. The effect of the free rotation of a swirl device on the thermal performances and friction behaviors are investigated experimentally. Five turbine-type swirl generators with and without free rotation are inserted and installed equally distant along the test section. In the present study, DI water is used as a testing fluid and flows under a turbulent flow regime. A common stainless steel tube with an OD of 10mm, ID of 9.2mm, and length of 2.3m is used as the test tube. A DC power supply is used to supply the heat load to the test section in order to meet the constant heat flux boundary condition. The data for a common smooth tube are compared with the data for fixed (FTSG) and freely rotating turbine type swirl generator (RTSG). The measured data illustrate that the heat transfer performance of the tube with RTSG inserts is 6.3% and 56% higher than that of the FTSG insert and the conventional smooth tube, respectively. Moreover, the heat transfer coefficient significantly increases when the fluid flows pass the RTSG and FTSG inserts. However, inserting the RTSG and FTSG into the common smooth tube results in an increase of the pressure drop. The tube with RTSG inserts gives the lowest pressure drop.

An experimental investigation of the heat transfer and pressure drop characteristics of a circular tube fitted with rotating turbine-type swirl generators

Heat transfer enhancement and flow behaviors in horizontal circular tubes installed with five rotating turbine-type swirl generators (RTSG) are presented experimentally. This type of RTSG is an innovative design that has not been seen in the previous research. Deionized water is used as a working fluid and flows through the test section under turbulent flow conditions. A smooth, stainless steel tube 9.2mm in ID, 0.4mm in thickness, and 2.3m in length is used as the test section. RTSG made from aluminum, with a twisted angle of 60° and a length of 2cm, are located at 0.46m equally distant along the test section. When fluid flows through the RTSG, continuously free rotations are observed, and swirl flow after RTSG is created. A DC power supply is used to supply heat load to the test section. Compared with a common, plain tube (without rotating swirl devices), the experimental results indicate that the local heat transfer coefficient of the tube with RTSG inserts is higher than that of the common, plain tube, and they increase when the working fluid flows through the RTSG. Similarly, the wall temperatures of the tube with RTSG inserts are lower than those of the common tube. However, the pressure drop of the tube fitted with RTSG is significantly greater than that of the common, plain tube.

Study on Swirl Composite Fluidization Mode with Circulating Fluidized Beds for Flue Gas Desulfurization

Circulating Fluidization Bed (CFB) for Flue Gas Desulfurization (FGD) is widely used. But its desulfurization efficiency is lower than Wet FGD. Its investment is not much lower than Wet FGD. Flow field of CFB for FGD is hard to be uniform. Swirl Composite Fluidization Mode (SCFM) was brought forward compared to Venturi Fluidization Mode (VFM). Experiment and simulation under cold condition was proceeded. From the test, flow field along axis and in cross-sections for SCFM are uniform. Turbulent velocity fluctuation is violent. And particles concentration is high. SCFM has better flow effect than VFM. Uniformity increases with higher superficial velocity and more tangential swirl devices. Recommended tangential swirl devices number is between 3-6. SCFM technology has good foreground.

Computational fluid dynamic analyses of catalytic combustors for 100 kW-class molten carbonate fuel cell

The asymmetric inner structure of a catalytic combustor causes wall cracking because of regional overheating. Thus, a symmetric shape is proposed in the present work and analyses of the computational fluid dynamics of the existing combustor and the proposed type have been performed. A simulation of the revised combustor without a swirl device revealed that the flow of gases is concentrated on the center of the combustor and only catalysts around the center are used. In the revised combustor with a swirl device, the overall temperatures were estimated to be uniform. However, near the swirl device, high temperature exceeding 1,700 K was measured. Therefore, a heatproof surface coating on the swirl device is necessary for protection of the material. At the initial start-up of the catalytic combustor, hydrogen and natural gas are used. When only natural gas is used, the simulation indicated that the gas does not burn in the revised combustor without a swirl device. However, in the combustor with the swirl device, methane of 34.8% volume burns in the simulation. On the other hand, when hydrogen and natural gas are burned together, methane of 91.7% volume burns in the simulation.

Energy saving device of stator for marine propellers

Αbstract This study describes a detailed procedure for design of marine screw propellers in combination with stators, also known as fixed guide vanes or pre/post swirl devices, based on lifting line theory. The design procedure presented here involves the realistic representation of the propeller slipstream, which is contracted form of helical vortices. The slipstream shape is allowed to deform and to align with the direction of local velocity that is the sum of the inflow wake velocity and induced velocity. As the slipstream deformation is the key parameter in the design of reaction type performance improvement devices, the design methodology is applied to a stator device behind the propeller, and then the hydrodynamic performance of the combined propulsor is analyzed. Furthermore a CFD analysis based on Finite Volume Method is applied. The results from both methods are compared and discussed.