Blade Rotational Speed Research Articles

Propeller design and verification studies for 30–35 meter tugboats

The invention of the propeller, the breakthrough of modern shipping, has supported a much more efficient use of the seas. The propeller consists of helical surfaces placed at equal intervals around a cylinder and can be characterized as ship elements that work like a screw in water. As a result of the rotation of the propeller, the ship to which the propeller is attached makes a translational movement due to the effect-response of the fluid on the propeller.This study includes propeller design and verification as part of a comprehensive project. The scope is the design of a 2m diameter aluminum bronze propeller with 4 blades of 50° backward inclination used on 25–30 m tugboats. Both static and CFD (Computational Fluid Dynamics) analyses were performed and design verification studies were carried out. The forces due to seawater, geometry of the blades, seawater flow rate and blade rotation speed were taken into consideration.The maximum deformation value of 1.7616 mm was obtained at the applied mode 4 value. When all the results obtained were evaluated, there was no need to go back to the propeller design. First of all, the angle value in the propeller geometry was found to be ideal for 50° angle in terms of both strength and fluid mechanics.

Numerical analysis of flow and heat transfer characteristics of unsteady film cooling of HPT shroud under high-speed rotation sweeping of the rotor blade

3D URANS simulations were performed to investigate the influence of high-speed blade rotation sweeping effect on the unsteady multi-hole film cooling performance of a high-pressure turbine (HPT) shroud. The blade rotation speed was 10,000 rpm and 15,000 rpm, the associated Strouhal numbers (St) were 2.35 and 3.52, and the blow ratio (M) was varied from 0.5 to 1.5. The instantaneous and time-averaged characteristics of film outflow mass rate, pressure distribution, film cooling effectiveness (FCE), and convective heat transfer coefficient (CHTC) of the HPT shroud with and without impinging jets were determined. The results show that the St and M have a substantial impact on the distribution of the FCE and CHTC on the shroud surface. At a high St and M, the FCE on the shroud surface is greater and more sensitive to the rise in M. As St increases, the suppression effect of the tip leaking vortex (TLV) on film and FCE on the shroud surface improved. The increased impingement jet effect has minimal impact on the FCE of the shroud. Under a high-speed blade rotation sweep, the net heat flux on the shroud wall with impingement/film cooling falls by approximately 22% when compared to the uncooled shroud surface.

Digital twin technology for wind turbine towers based on joint load–response estimation: A laboratory experimental study

An accurate estimation of dynamic loads and structural dynamic responses is deemed an indispensable prerequisite for developing trustworthy digital twin (DT) models of dynamically excited structures. Traditional joint load–response estimation (JLRE) algorithms necessitate a full-rank feedthrough matrix, implying that accelerometers are required at all degrees of freedom with input loads. If an unknown input is a bending moment or torque, the rotational acceleration must be measured, which is usually difficult, if not impractical, in real applications. Therefore, the applications of the traditional JLRE in wind turbines (WTs) are rather limited due to the complex excitation mechanism. However, the unified linear input and state estimator (ULISE) algorithm presented in this paper eliminates this constraint. This paper experimentally tested this algorithm on an operating 1:50 scaled WT model. The influences from blade rotation were considered. A comprehensive structural health monitoring (SHM) sensing system was deployed on the WT tower to measure the tower's dynamic responses. A camera system, which integrated digital image correlation (DIC) technology and binocular stereo vision technology, was also adopted. The unknown excitations and unmonitored dynamic responses of the WT tower were estimated simultaneously using the ULISE algorithm. The reconstructed strain and acceleration responses achieved high accuracy, with a normalized root mean square error less than 9%. The blade rotation had a notable impact on the WT tower, primarily manifested as a bending moment whose dominant frequency was corresponding to the blade's rotational speed. Such joint estimations could function as the virtual sensing of unknown inputs and responses in the DT model of the WT tower, which will enable DT-based online remote structural condition assessment and preventive maintenance in the future.

Disentangling mechanisms responsible for wind energy effects on European bats

Mitigating anthropogenic climate change involves deployments of renewable energy worldwide, including wind energy, which can cause significant impacts on flying animals. Bats have highly contrasted responses to wind turbines (WT), either through attraction increasing collision risks, or avoidance leading to habitat losses. However, the underlying mechanisms remain largely unknown despite the expected rapid evolution of WT size and densities. Here, using an extensive acoustic sampling (i.e. 361 sites-nights) up to 1483 m from WT at regional scale, we disentangle the effects of WT size (ground clearance and rotor diameter), configuration (density and distance), and operation (blade rotation speed and wake effect) on hedgerow use by 8 bat species/groups and one vertical community distribution index. Our results reveal that all WT parameters affected bat activity and their vertical distribution. Especially, we show that the relative activity of high-flying species in the community was lower for higher WT density and lower ground clearance. Medium-flying species were sensitive to wind turbine distance, with either attraction or avoidance depending on proximity to the wake area and wind conditions. Specifically, wind turbine distance, wake effect and their interaction each affected the activity of one, three, and three species out of eight, respectively. Blade rotation and rotor diameter affected the activity of four and three species/groups, respectively, and ground clearance affected the activity of five ones. Taken together, WT configuration, operation, and size parameters affected the activity of three, five, and seven out of eight species/groups, respectively. These results call for the consideration of all these factors when assessing the ecological sustainability of future wind farms. The study especially advocates to avoid high WT densities, large rotors, and to site WT as far as possible from optimal habitats such as woody edges and not between them and the source of prevailing winds, in order to limit bats-WT interactions.

Quantitative and Multiplexed Chopper-Based Time-Gated Imaging for Bioanalysis on a Smartphone.

Smartphones are emerging platforms for point-of-care diagnostics (POCDs), where the on-board camera is, for example, used to image fluorescence. Many laboratory instruments are capable of time-gated (TG) photoluminescence (PL) measurements─an analytical method leveraged by multiple commercial assay kits. When paired with long-lived PL emitters such as luminescent lanthanide complexes (LLCs), time-gating eliminates background from sample autofluorescence and many other sources. This capability is amenable to minimally processed samples and would thus be useful for POCDs on a smartphone-based platform. Here, we report a double-chopper design for TG PL imaging using a portable, 3D-printed, smartphone-based device. The rotation speed, dimensions, and overlap of the chopper blades and gaps set the timing parameters, with delay times on the order of hundreds of microseconds to milliseconds. The device was capable of quantitative TG imaging of PL from terbium(III) and europium(III) LLCs, including rejection of short-lived PL background from serum and tissue phantoms, spectral and temporal multiplexing, a model time-gated Förster resonance energy transfer (TG-FRET) assay, and imaging of cells. As the first smartphone-based demonstrations of these important analytical capabilities, this work is an important foundation for developing POCD methods based on TG PL imaging.

Dynamic Regulation Process of the Variable-Geometry Power Turbine

In this paper, the dynamic regulating process of a variable-geometry power turbine is investigated through wind-tunnel experiments. Particle image velocimetry is used to obtain the dynamic evolution of the flowfield in the cascade passage, including two adjustment processes of increasing and decreasing the throat area. During the test, snapshots of the clockwise/counterclockwise rotation of a blade in the range of to are processed with a piecewise time-averaged method. The results indicate that the macroscopic change in the flowfield structure mainly appears in the wake region and the high-velocity region. In this process, the velocity and flow angle change monotonously with the blade rotation. The change rate of velocity is determined by both the blade position and the dimensionless outlet location . The overall change rate of velocity when the blade approaches the design position is higher than that at other positions, and the airflow near the suction surface is more sensitive to the adjustment of the cascade geometry compared with that near the pressure surface. As for the flow angle, the specific value is mainly determined by the blade position, and the variation law is related to the blade rotation speed.

Separation and Characterization of Plastic Waste Packaging Contaminated with Food Residues.

In this paper, we present the development of a novel processing technology to tackle hard-to-recycle plastic packaging waste contaminated with food residues. The proof-of-concept (POC) technology can effectively separate food residual amounts from plastic waste materials to a level acceptable for further re-use or recycling of the plastic packaging. To assess this technology, we have conducted spectroscopic, thermal, and calorimetric characterizations of the obtained fractions, such as cleaned mixed plastics (CMP), food waste with mixed plastics (FWMP), and a mixture of microplastics (MP). The analyses were carried out with the aid of Fourier-Transform Infrared spectroscopy (FT-IR), Thermo-Gravimetric Analysis (TGA), Microcone Combustion Calorimetry (MCC), and 'bomb' calorimetry. The highest ratio of CMP to FWMP and the lowest amount of MP were obtained utilizing 700 rpm blade rotational speed and 15 s residence time of contaminated plastics in a cutting mill chamber. The plastics were freed from food contamination by 93-97%, which highlights a strong potential of the POC as a solution for 'dry-cleaning' of similar wastes on a larger scale. The main components of the CMP fraction were low-density polyethylene (LDPE), polypropylene (PP), and polyethylene terephthalate (PET), which are recyclable plastics. The knowledge and understanding of thermal degradation behaviours and calorimetric attributes of separated fractions, determined in this study, are essential in informing the industrial players using pyrolysis as a technique for recycling plastics.

Experimental Investigation for a Small Helicopter in Hovering and Forward Flight Regimes

In this effort, experiments are conducted for a small-scale remotely controlled (RC) helicopter in both hovering and forward flight modes. An open wind tunnel type is used as a source of forward airflow for the helicopter model with flow speed (v∞) ranges from 3 to 12 m/s. A test rig was designed and manufactured to provide safe and reliable averaged thrust measurement in hovering and forward flight regimes. The helicopter is controlled via an adhoc-designed graphical user interface program using a microcontroller along with sensors to measure the blade collective pitch (θ0), rotational speed (Ω), and shaft angle of attack (αs). The averaged thrust for the helicopter is measured and compared with blade element theory and an unsteady model based on strip theory. Measurements are conducted for six rotational speeds and five collective pitch angles in hovering mode. Additionally, forward flight measurements were conducted for five rotational speeds, five collective pitch angles, two forward airflow speeds, and two shaft angles of attack. Uncertainty analysis is performed to certify a statement of the obtained results by combining both bias uncertainty from measuring instrument specifications and precision uncertainty through experimental repeatability. Results can be used for preliminary sizing of rotors for such small helicopters in both flight modes.

Mathematical modeling of a hybrid magnetic gear for an autonomous low-power wind turbine

In traditional wind turbines, a mechanical gearbox is used to transmit the torque. This device converts the low rotation speed of the wind turbine blades into the high rotation speed of the generator shaft. Mechanical gearboxes are characterized by low reliability. They consist of rotating gears, all the torque between which is transmitted through the contact of the teeth at one point, which is accompanied by friction. Magnetic multipliers are more efficient than gear reducers. They contain no wearing parts and have a relatively high torque density. The modulator transforms the magnetic field between the inner and outer rotor, due to which the speed of rotation changes. This device has a number of advantages over a mechanical gearbox - the interaction between rotating elements (torque transmission) occurs over their entire area, while the gears of mechanical gearboxes perceive all the transmitted force at one point of contact between them. Research of autonomous wind turbines built on the basis of magnetic gearboxes is a relevant direction. This will reduce operating costs, increase the efficiency of converting wind energy into electricity, and increase the reliability of the wind turbine as a whole. The purpose of the work is the development of a two-dimensional field mathematical model of a hybrid magnetic gearbox for the evaluation of its parameters and characteristics and the optimization of its geometric dimensions. A generator with a built-in magnetic multiplier is the object of this study. The magnetic multiplier during operation creates a rotating magnetic field that can be used to induce emf in the generator winding. Such a generator is more compact than a gear drive, so this option was chosen as a prototype in this study. Geometrical models of a hybrid generator with a magnetic gearbox were developed and numerical field mathematical models were developed for the analysis of its parameters and characteristics. An analysis of the electromagnetic field and characteristics of the basic generator was carried out in the COMSOL Multiphysics software complex, on the basis of which optimization of its geometric dimensions was carried out to optimize mass and dimensional indicators

Study on the separation performance of a decanter centrifuge used for dewatering coal water slurry

The decanter centrifuge is widely used in the dewatering process of coal water slurry. In order to improve the separation performance of the decanter centrifuge, the influence of pitches, spiral blade inclination angles and rotational speeds on the separation performance was obtained by the combination of simulation and theoretical analysis. The results indicate that the higher pitch would lead to the decrease of the sediment stack height in front of the spiral blade and the residence time of the particles. With the increase of the pitch, the axial thrust and the slag solid content rate are increased first and then decreased. The best pitch is 258 mm. Using a backward tilting spiral blade can improve the distribution of sediment and enhance the radial extrusion of the spiral blade to sediment. Increasing the rotational speed can increase the tangential velocity and settling velocity of the material. When the rotational speed is less than 3000 rpm, increasing the rotational speed can improve the separation performance effectively. This paper provides references for optimizing the structure and improving the separation performance of the decanter centrifuge in the dewatering process of coal water slurry.

Research on cleaning technology and damage assessment of single-stage compressor rotating blades with dry ice as agent

Numerical investigations based on the Euler-Lagrange approach were carried out first to verify the efficiency of the on-wing cleaning of the compressor blades of aero engines by taking dry ice instead of aqueous solvents as agent. The coupling between particles and the gas phase as well as the interaction between particles and blades were considered by means of comprehensive simulations of the movement of dry ice in the blasting device and the rotating blade channel of the single-stage compressor. Then, the factors that influence dry ice cleaning efficiency were verified and analyzed through dry ice cleaning test on single-stage compressor rotating blades. Finally, the damage assessment of the blade surface and coating under low temperature and impact force was completed. According to the results, the erosion rate cloud map obtained by simulation calculations and the cleaning effect image obtained by the test both showed that the interaction between particles and blades was mainly in the area near the leading edge of the blade. The main variables that affected the cleaning efficiency were the blade rotating speed, the dry ice mass flow rate and the cleaning angle. Furthermore, the highest cleaning efficiency was acquired when the blade rotational speed was 2500 r/min, the dry ice mass flow rate was 6 kg/min and the cleaning angle was 90°. Under these conditions, the blade surface and the coating are not damaged. Dry ice cleaning is a feasible technology in terms of on-wing aero engines, which has broad prospects of applications.

Numerical study of the mixing of micron particles in a vane mixer

As the research and application of micron particles are intensified, higher requirements for continuous flow mixing of multiple micron particles have been put forward. This study is based on rotating blades in the flow field to generate a vortex through which various micron particles are mixed. The particle mixing device designed in this study has a simple structure and small size advantages. The particle mixing model for coupled flow field study is established by using the finite element analysis method to realize the study of multiple micron particle mixing. The effects of blade shape, blade size, blade rotation speed, and inlet particle entry interval on the mixing impact are analyzed in the study. In this study, the factors affecting the particle mixing effect were analyzed by counting the number of outlet particles and plotting the flow lines in the mixing chamber. Optimization of the mixer scheme based on the influencing factors obtained from the study resulted in a high mixing effect of the designed particle mixer, which can provide a significant reference value for the subsequent micron particle mixing scheme design.

Investigation of ice accretion effect on the aerodynamic characteristics of a wind turbine blade tip after a short icing event

The paper investigates the flow behavior near the NACA 64-618 airfoil profile of the blade tip section of a wind turbine for electric power production after a short icing event. The flow simulation considering the rotation speed of the wind turbine blade is performed to assess the effect of icing on the aerodynamic characteristics. Degradation of aerodynamic characteristics affects the electrical energy production of the wind turbine. The aerodynamic lift and drag coefficients are calculated for different angles of attack. The flow velocity fields near the airfoil are analyzed. The pressure coefficient distributions along the profile surface are obtained. The points of flow stall and changes of aerodynamic characteristics at different angles of attack are determined.

Analysis of Cyperus esculentus–Soil Dynamic Behavior during Rotary Tillage Based on Discrete Element Method

Considering the problems of low soil fragmentation rates, high working resistance, and high energy consumption in the harvesting process of Cyperus esculentus in China, a method of Cyperus esculentus harvesting based on counter-rotation digging is proposed. The mechanism of interaction between the rotary tillage blade and Cyperus esculentus–soil is systematically investigated, and the vertical and horizontal disturbance performance of the positive and counter-rotating harvesting methods on soil and Cyperus esculentus is compared and analyzed. The results of the experiment showed that the intensity of soil and Cyperus esculentus disturbance by counter-rotation increased by 166.67% and 297.78%, respectively, and the effective disturbance time of soil and Cyperus esculentus increased by 133.33% compared to that of positive rotation. The working depth and rotation speed of the rotary tillage blade were the most significant for soil and Cyperus esculentus disturbance intensity. The working depth increased from 150 mm to 170 mm, and the soil disturbance intensity increased by 17.91% and 21.37% for positive and counter-rotating operation, respectively, and the rotation speed of the rotary tillage blade increased from 270 rpm to 330 rpm, and the soil disturbance intensity increased by 28.85% and 35.29%, respectively. Compared with the positive rotation operation, the Cyperus esculentus counter-rotation soil fragmentation rate increased by 4.09%, the Cyperus esculentus damage rate decreased by 10.69%, and the buried fruit rate decreased by 7.38%. This paper helps to understand the interaction mechanism between the rototiller and Cyperus esculentus–soil and lays a theoretical foundation for the subsequent design and optimization of the Cyperus esculentus digging device.

Experimental Study on the Recovery of Lignin from Black Liquor by Blade Dynamic Cross-Flow Filtration Device

The separation and recovery of lignin in black liquor is a hot topic in current research. Ceramic membrane technology has become the main method of lignin separation in black liquor due to its advantages of green environmental protection, high efficiency and high recovery rate. However, in the separation process, the problem of ceramic membrane fouling has always existed and has become the key to hinder its continuous separation. Aiming at the problem that the existing filtration methods can not meet the continuous separation of lignin in black liquor, this paper proposes to apply the blade dynamic cross-flow filtration device to the separation process of lignin in black liquor, and the influence of blade rotation speed on the separation performance is studied experimentally. The results showed that increasing the rotating speed of the blade could effectively reduce the accumulation of filter cake on the membrane surface and achieve the purpose of improving the filtration flux.

ВПЛИВ ШВИДКОСТІ ВІТРУ НА РОБОТУ ВІТРЯНИХ ТУРБІН З DFIG ГЕНЕРАТОРОМ НА ВІТРЯНИХ ЕЛЕКТРОСТАНЦІЯХ

The purpose of the work: Determination of the mechanical and electrical parameters of the turbine with a DFIG generator at different values of the wind speed at start-up by means of simulation in the Matlab Simulink software environment. Methodology: a comprehensive approach that includes theoretical research and solving the following tasks: to establish characteristic moments of time in the process of starting a plant with a DFIG generator as a source of electricity; determine the angular speed and braking torque of the turbine during its start-up at different wind speeds; determine the active and reactive power of the DFIG generator during its start-up at different wind speeds. Results: Simulation of the operation of the wind generator was carried out in the Matlab Simulink software environment, in which a system for obtaining electrical energy from wind energy (DFIG) was built. The reactive power of electric motors, the efficiency of which depends on the power factor, is presented Scientific novelty: when the wind speed changes, a change in reactive power and a redistribution of the electric moment of the generator and the torque of the wind are observed. Full power, which is the vector sum of active and reactive power, and is supplied to the network by electric generators. Analysis of graphical dependencies allows you to see changes in time of active and reactive power, which cause changes in torque and speed of rotation in the wind generator. Practical significance: Studying the processes in the wind generator with the help of the proposed model allows you to compare the parameters of their operation under different modes and given wind speeds, determine the maximum values of the mode parameters, and obtain the necessary information for the implementation of reactive power compensation measures. The proposed model also makes it possible to find ways to improve the wind generator and the system for obtaining electrical energy for the operation of enterprises during the intensive reconstruction of Donbas. Key words: energy, active power, reactive power, wind generator, wind speed, transformer, generator, torque, blade rotation speed

Design & development of a Nano Wind Turbine

In this paper, the design & development of a Nano Wind Turbine is presented. Small-scale wind turbines have received less attention compared to their large-scale counterparts, prompting the need for studies in this area. This research focuses on the dynamic properties of "Glass reinforced fiber composite" blades in a nano wind turbine, providing both experimental and analytical results. The study investigates crucial parameters such as the natural frequency and mode shapes of the turbine, which are necessary for determining its performance and lifespan. Additionally, the results are used to set safe blade rotation speeds. Using Creo Parametric software, a detailed ANSYS Workbench 14.0 model is developed for simulation, incorporating the material properties of Glass reinforced fibre composite. The mathematical and experimental results are compared, and the first four modes are found to be within acceptable limits, verifying the dynamic properties of the Glass reinforced fiber composite. The work done & presented in this paper is the result of the mini-project work that has been done by the first sem engineering students of the college and as such there is little novelty in it and the references are being taken from various sources from the internet, the paper is being written by the students to test their writing skills in the starting of their engineering career and also to test the presentation skills during their mini-project presentation. The work done & presented in this paper is the report of the assignment / alternate assessment tool as a part and parcel of the academic assignment of the first year subject on nanotechnology & IoT.

Investigation of fragment separation during a circular saw blade cutting rock based on ANSYS/LS-DYNA

Circular saw blades are widely used in stone processing. The circular saw blade cutting hard rock numerical simulation model based on ANSYS/LS-DYNA was established to investigate the complex dynamic problem in rock cutting. The failure mechanism of the rock and the influence of cutting parameters on the cutting force and rock fragments were studied by numerical simulation. The results demonstrated that the failure modes of the rock were mainly tensile failure with some shear failure and compressive failure. The cutting force and the number of fragments increased with the feed speed. With the increasing circular saw blade rotational speed, the cutting force and the number of fragments decreased and tended to stabilize. With the distance between the circular saw blades increasing, the cutting force and rock fragments number increase and then maintain basic stability, and when the distance between double circular saw blades reaches 25 mm, it will form a completed rock plate and the interaction of circular saw blades will decrease. The numerical simulation can accurately simulate rock breakage and force when a circular saw blade cuts rock.

Development of Orodispersible Ibuprofen Tablets Based on a Polymer-drug Complex

Introduction. Orodispersible dosage forms are a very promising direction in the development of dosage forms. Such dosage forms are designed for both systemic and local action of the active pharmaceutical ingredients that make up their composition. Active pharmaceutical ingredients from orodispersible forms enter directly into the systemic circulation, bypassing the "first pass effect".Aim. Development of orodispersible tablets based on the Eudragit® EPO/ibuprofen polymer-drug complex and evaluation of ibuprofen release from the resulting system.Materials and methods. Samples of the polymer-drug complex (PDC) were obtained with different ratios of EPO and ibuprofen, as well as with different mixing orders. Turbidimetric studies to find the stoichiometry of the resulting EPO/IB PLC were performed spectrophotometrically (Lambda 25, PerkinElmer, U.S.A.) at a wavelength of 600 nm. Thermal analysis was performed by modulation differential scanning calorimetry (mDSC) on a Discovery™ DSC instrument (TA Instruments, U.S.A.). Samples sealed in Tzero aluminum pans (TA Instruments, U.S.A.) were scanned in the temperature range from 0 to 250 °С at a speed of 2 °С/min. IR spectra were recorded on a Nicolet iS5 FT-IR spectrometer (Thermo Fisher Scientific, U.S.A.) with an ATR nozzle, in the range from 500 to 4000 cm-1. Drying of samples of complexes and dispersible tablets was carried out in a FreeZone 1L laboratory freeze dryer (Labconco, U.S.A.) for a 24 hours at a temperature of –49 °C and at a pressure of 0.350 mbar. The drug release was evaluated on a dissolution tester DT 828 (ERWEKA GmbH, Germany) in a volume of 900 ml, at 37 ± 0.5 °C and a blade rotation speed of 50 rpm.Results and discussion. Studies on the formation of PDC Eudragit® EPO/ibuprofen (EPO/IB) were carried out at various molar ratios. On samples of PDC and individual components, bands are observed that are characteristic both for EPO – at 2770 and 2820 cm-1, confirming the presence of non-ionized dimethylamino groups, and at 1725 cm-1, corresponding to the stretching vibrations of carboxyl groups. A new band is appeared at 1573 cm-1, which confirm the formation of ionic bonds between carboxylate groups of IB and ionized dimethylamino groups of EPO. The mDSC thermograms of the samples are characterized by a single glass transition temperature (Tg) at 27,3 ± 0,3 °С (for molar ratio 1 : 2) and 44,9 ± 0,4 °С. (for molar ratio 1 : 1), which confirm the formation of polymer-drug complexes. Received PDC Eudragit® EPO/ibuprofen in a molar ratio of 1 : 2 and 1 : 1 and oral dispersible tablets based on them by lyophilization. The resulting systems are characterized by immediate release of IB with maximum rates at 30 min for a 1 : 1 composition and 60 min for a 1 : 2 composition.Conclusion. Eudragit® EPO/ibuprofen polymer drug complex can be used to develop orodispersible tablets providing immediate release of IB.

Hole Cleaning Performance of V-Shaped Hole Cleaning Device in Horizontal Well Drilling: Numerical Modeling and Experiments

The application of hole cleaning devices can effectively solve the hole cleaning problem during the drilling of horizontal wells. Improving the hole cleaning performance is directly related to subsequent drilling time and cost. In this paper, the solid–liquid two-phase hydrodynamic characteristics under the action of the V-shaped hole cleaning device for drilling horizontal wells were studied experimentally and numerically. The decay law of spiral flow induced by the V-shaped hole cleaning device was obtained numerically using the commercial CFD code “Fluent” by changing the blade rotational speed, blade helix angle, and consistency coefficient of drilling fluid. The helix angle will cause the flow direction of local fluid to deflect. The swirl intensity of spiral flow increases significantly with an increase in rotational speed. The hole cleaning performance was better when the helix angle was from about 10 to 20 degrees. Increasing the fluid consistency coefficient will rapidly make the spiral flow decay, resulting in a shorter effective action distance and a worse hole cleaning effect. The simulation results were validated against the experimental results of the flow loop. Both experimental and simulation results showed that the hole cleaning performance was improved by using the V-shaped hole cleaning device. The very good agreement achieved between the results has presented an opportunity to study the hole cleaning effect of a hole cleaning device in unsteady state conditions. The results will provide theoretical guidance for efficient hole cleaning using V-shaped hole cleaning devices for horizontal well drilling.