Evaluation of the Erosion Characteristics for a Marine Pump Using 3D RANS Simulations

In the present study, an erosion analysis of an industrial pump’s casing and impeller blades has been performed computationally. Effects of various critical parameters, i.e., the concentration and size of solid particles, exit pressure head, and cavitation on the erosion rate density of the casing and blade have been investigated. Commercial codes CFX, ICEM-CFD, and ANSYS Turbogrid are employed to solve the model, mesh generation for the casing, and mesh generation of the impeller, respectively. The Eulerian-Eulerian method is employed to model the pump domain’s flow to solve the two phases (water and solid particles) and the interaction between the phases. Published experimental data was utilized to validate the employed computational model. Later, a parametric study was conducted to evaluate the effects of the parameters mentioned above on the erosion characteristics of the pump’s casing and impeller’s blade. The results show that the concentration of the solid particles significantly affects the pump’s erosion characteristics, followed by the particle size and distribution of the particle size. On the other hand, the exit pressure head and cavitation do not affect the erosion rates considerably but significantly influence the regions of high erosion rate densities.

Analysis of Tube in Tube Heat Exchanger Fitted with Twisted Tape with Square Cut

Numerical investigations of heat transfer and friction factor characteristics in swirling flow conditions using CFD simulation. A commercial CFD package, Ansys R1 2021, was used in this study. 3D models for circular tube fitted with Square-cut twisted tape (QCT) inserts with two pitch 100mm, 50 mm and different cut depths (d = 4 mm, 5mm and 7 mm) were generated for the simulation. Insertion of twisted tapes into the tubes of the heat exchangers is important for enhancement of heat transfer to increase the performance of heat exchangers. In the present Research work, computational analysis has been carried out to analyse the enhancement of rate of heat transfer using Square cut cross sectional twisted tape inserts in a pipe heat exchanger. Geometrical model of heat exchanger has been generated and computational mesh is created using ICEM CFD, an advanced meshing software. The analysis has been carried out for plain tube and with Square cut cross sectional twisted tape inserts with different twist ratio analyse the temperature distribution, velocity distribution and pressure distribution along the tubes and shell using ICEM CFD.

Leading Edge Shape Optimization of Whitcomb IL Airfoil in Transonic Flow Using a Multi-Objective Genetic Algorithm (MOGA)

Leading edge shape optimization of transonic airfoils requires creating an airfoil surface that reduces the drag divergence due to transonic shocks by either delaying them or reducing their strength at a given transonic cruise speed while maintaining the lift. Aircrafts like Boeing 757, Airbus A300, Boeing 777 and McDonnell Douglas AV-8B Harrier II use Whitcomb IL supercritical airfoil for efficient aerodynamic performance in transonic conditions. This study employs a multi-objective genetic algorithm for shape optimization of leading edge of the Whitcomb IL airfoil to achieve three objectives, namely dilation of shock, reduction in leading edge radius and increment of lift at a given transonic Mach number and at the given AoA. The commercially available software ICEM CFD and Fluent are employed for calculation of the flow field using the RANS (Reynolds-averaged Navier-Stokes equations) in conjunction with a two equation turbulence model. It is shown that the (MOGA) Multi-objective genetic algorithm can generate superior airfoil compared with Whitcomb IL airfoil by achieving three objectives. The optimized airfoil configuration is validated by wind tunnel testing facility.

Numerical-experimental comparison of radial fans applied in pneumatic transport of agricultural fertilizer spreaders

ABSTRACT This study presents a numerical and experimental comparison of two different types of radial fans used in an agricultural fertilizer spreader at a rotation of 4000 rpm. The numerical analysis was validated through experiments conducted on a test bench using a hot-wire anemometer for velocity measurements and a Pitot tube for pressure readings. A simulation of the agricultural fertilizer spreader was carried out after the experimental validation of the mathematical models of the radial fans on the test bench to evaluate the air distribution behavior along the application nozzles, which was compared to the experimental results. A turbulent mean-field was obtained using the Reynolds Averaged Navier Stokes (RANS) and the k-Epsilon turbulence model was used for two equations. The computational fluid dynamics software CFX 18.1 was used to solve the transport equations. Unstructured tetrahedral meshes generated by the ICEM CFD 18.1 software were used in all models. The applied method is adequate and able to reproduce the fluid-dynamic behavior of airflow in pneumatic systems of agricultural fertilizer spreaders, avoiding the need for prototypes.

Aerodynamic and Experimental Analysis of Bio-mimic corrugated dragonfly aerofoil

In this work, experimental and computational approach is used to understand the corrugation attitude of a bio-inspired dragonfly mimicked corrugated airfoil at low Reynolds number varying from 15000 to 75000 to understand the advantages of pleated corrugated airfoil. The CFD analysis is carried out on the 2-dimensional bio-mimetic corrugated ‘Pantala flavescens’ dragonfly forewing to predict the aerodynamic characteristics of the corrugated dragonfly aerofoil with varying angle of attack from 0° to 8°. The computational analysis of the wing profile is done using the ANSYS-19 ICEM CFD and FLUENT software. For the experimental test, the model is printed in 3-D printer machine and tested in subsonic Wind Tunnel at different speeds and different angle of attacks using a wind tunnel 6-component balance. The computational simulation reveals the exemplary results of the pleated airfoil (corrugated aerofoil) with new design constraints. Finally, the computational result is validated with experimental results.

Active flow control of a diffusing S-duct

Realization of the S-duct benefits requires scrutiny of certain phenomena such as swirls, secondary flows, and flow distortion creation which are related to the S-duct due to its physical curvature. The first phase of the study investigated the flow field inside the S-duct. NASA Glenn research center’s S-duct was adopted in this study. Geometry was created in SOLIDWORKS and mesh was done using ICEM CFD. Numerical analysis was carried out in ANSYS Fluent software. A turbulence model named kω-SST was incorporated. Boundary conditions were set so as to match the experimental test done by NASA Glenn research center. Computational results showed a significant agreement with the experiment. The results also affirmed the presence of the secondary flow and flow distortion at the aerodynamic interface plane. The second phase of the study investigated the ability to control the flow and reduce the flow distortion on the engine fan face. Results showed a 10% flow distortion reduction and the secondary flow severity decreased by 16.5% on the aerodynamic interface plane (AIP). Keywords: Active Flow Control (AFC), Aerodynamic Interface Plane (AIP), Flow Distortion, S-duct

Conceptual Design and Hydrodynamic Research on Unmanned Aquatic Vehicle

Autonomous Underwater Vehicles (AUVs) are one of the significant types of aircraft, which are traveled in submarine by the pre-programmed control process. At the present time AUV is being projected for many serious applications together with fault exposure on the dam, tragedy monitoring, naval supervision, and fisheries safety. Interest in AUVs for ocean investigation and mapping, inspection, and forecasting have emerged progressively, in which the AUVs design methods are implemented in submarine are regularly multi-rotor arrangement AUVs. In submerged applications, multi-rotor based AUVs are low proficient in terms maneuvering practicability, existence, as a result, the designer must make available an AUV, which has the high lifetime, high efficient in devise, more secure on-flight and low continuation cost in order to endure at the decisive environment. In this article proposed a unique AUV, called Unmanned Aquatic Vehicle (UAV) inspired by the approach of flying fish, this can able to maneuver in underwater with high competence, in which estimation of resourceful have been derived based on theoretical design, manipulation realization process, communication, a existence of a UAV. Advanced numerical imitation have the ability to solve decisive problem so in this paper used CFD, in which, the ordered grid of the computational models for dissimilar types of UAVs is generated by Ansys ICEM CFD 16.2. This discretized model represents as the imitation of UAV, which is used to forecast the flow performance of the orientation module, and examine the hydrodynamic belongings on its sub-components. In this article, ANSYS-FLUENT 16.2 software is used as arithmetical solver tool, which is a influential tool for solving troubles concerning fluid mechanics. Results of the velocity, pressure allocation, and drag coefficient are analyzed. The characteristics of the drag, lift, pitching moment partial by the distance to the sea underneath and the attack angle are studied, which provided the path for UAV intend optimization

Numerical Analysis of Protrusion Effect over an Airfoil at Reynolds Number -105

Need of micro aerial vehicles and Unmanned Air Vehicles is increasing due to military, defense and civilian requirements. These vehicles fly at very small Reynolds numbers and have to move in confined spaces with a bare minimum speed, to achieve high lift coefficient is the main concern. The main focus of this research paper is to carry out the computational analysis and study the unsteady flow over NACA0012 airfoil with right angle triangular protrusion at the Reynolds number 105 . The location of the protrusion is 0.05c, with three different heights of protrusion 0.005c, 0.01c, and 0.02c, normal to the surface of the airfoil. Geometric modeling and grid generation are created using the ICEM CFD software and numerical analysis carried out using commercial CFD Software at various angle of attacks ranging from 00 to 160 with 2 0 intervals. Numerical validation has done and compared. The results obtained from the research work is recommend that for smaller protrusions the lift and drag coefficients are unaffected in the low angle of attacks while the lift characteristic is significantly improved at the higher angle of attacks.

Numerical Investigation of a Hydropower Tunnel: Estimating Localised Head-Loss Using the Manning Equation

The fluid dynamics within a water tunnel is investigated numerically using a RANS approach with the k- ε turbulence model. The computational model is based on a laser scan of a hydropower tunnel located in Gävunda, Sweden. The tunnel has a typical height of 6.9 m and a width of 7.2 m. While the average cross-sectional shape of the tunnel is smooth the local deviations are significant, where some roughness elements may be in the size of 5 m implying a large variation of the hydraulic radius. The results indicate that the Manning equation can successfully be used to study the localised pressure variations by taking into account the varying hydraulic radius and cross-sectional area of the tunnel. This indicates a dominant effect of the tunnel roughness in connection with the flow, which has the potential to be used in the future evaluation of tunnel durability. ANSYS-CFX was used for the simulations along with ICEM-CFD for building the mesh.

Locomotive Capabilities of a Free-Swimming Robotic Tuna

As we try and understand more about the oceans and the creatures that inhabit them, the need for effective modes of aquatic transportation becomes abundantly clear. Taking a step back from traditional propeller-based systems, we look toward nature and the millions of years of natural selection to find inspiration. The successful designs that have prospered vary greatly from creature to creature depending on their lifestyle. From rays to jellyfish, the propulsion methods used are tailored for a specific purpose. Considering the vastness of the oceans and our desire to explore them, a quick and efficient mode of locomotion would be well suited for this task. A great example of this type of swimmer can be found within the genus Thunnus. Tuna rely on a lift-based propulsion system classified as thunniform swimming. The majority of thrust from this propulsion method is derived from the caudal fin and part of the tail. As the tail sweeps through the water, interesting vortex structures are shed from the trailing edge of the lunate fin. Along with velocity components that travel parallel to the movement of the fish, two separate vortices are shed from the top and bottom inner surfaces of the caudal fin and meet at the lengthwise center axis of the fish. These can be best visualized from the flow velocity components analyzed within a plane just behind the caudal fin and perpendicular to the body length axis. Over time, a reverse Karman vortex street is formed from the combination of vortices from multiple tail beats. A robotic tuna and CFD model were created with the minimum number of joints to approximate thunniform swimming. A modified scotch yoke mechanism was used to convert uniform rotation of a brushless DC motor to oscillatory motion that mimics the tail of a tuna. A servo is mounted on the tail to provide an adjustable angle of attack for the caudal fin. The dynamic CFD model of the tuna employs overset meshing techniques created in ICEM CFD 18.2 and is simulated within ANSYS Fluent 18.2. The model is actuated at the start of the tail and the base of the fin to represent thunniform swimming. The body of the tuna is held static as steady flow is passed around the model. The flow velocity was chosen as an approximation of the speed of a tuna of comparable size and tail-beat frequency.