scholarly journals Velocity Flow Field Characteristic on Nozzle Cavity using Central Composite Design of Computational Method for Dry Ice Blasting System

2021 ◽  
Vol 2129 (1) ◽  
pp. 012020
Author(s):  
Mohamad Nur Hidayat Mat ◽  
Md Faisal Md Basir ◽  
Mohamad Farid Sies

Abstract In the development of dry ice blasting nozzle geometry, the critical process parameters depend on particle jet velocity. However, very few researchers have attempted sensitivity on the velocity flow area of specific nozzle geometric parameters. A numerical simulation approach was performed in this paper using Ansys Fluent to investigate different nozzle parameters on the velocity flow field. A two-dimensional model is solved iteratively using averaged Navier-Stokes under Eulerian flow description. It was found that the velocity value increases that reach 550 m/s with an increment of the nozzle area ratio of up to 20 without influencing convergent angle and the velocity magnitude drop linearly from 525 m/s to 505 m/s in with the rise of divergent length that swell up to 700 mm and with constant convergent angle and convergent length.

Author(s):  
Nur Alom ◽  
Ujjwal K. Saha

The Savonius rotor appears to be particularly promising for the small-scale applications because of its design simplicity, good starting ability, and insensitivity to wind directions. There has been a growing interest in recent times to harness wind energy in an efficient manner by developing newer blade profiles of Savonius rotor. The overlap ratio (OR), one of the important geometric parameters, plays a crucial role in the turbine performance. In a recent study, an elliptical blade profile with a sectional cut angle (θ) of 47.5° has demonstrated its superior performance when set at an OR = 0.20. However, this value of OR is ideal for a semicircular profile, and therefore, requires further investigation to arrive at the optimum overlap ratio for the elliptical profile. In view of this, the present study attempts to make a systemic numerical study to arrive at the optimum OR of the elliptical profile having sectional cut angle, θ = 47.5°. The 2D unsteady simulation is carried out around the elliptical profile considering various overlap ratios in the range of 0.0 to 0.30. The continuity, unsteady Reynolds Averaged Navier-Stokes (URANS) equations and two equation eddy viscosity SST (Shear Stress transport) k-ω model are solved by using the commercial finite volume method (FVM) based solver ANSYS Fluent. The torque and power coefficients are calculated as a function of tip speed ratio (TSR) and at rotating conditions. The total pressure, velocity magnitude and turbulence intensity contours are obtained and analyzed to arrive at the intended objective. The numerical simulation demonstrates an improved performance of the elliptical profile at an OR = 0.15.


2012 ◽  
Vol 29 (3) ◽  
pp. 478-484 ◽  
Author(s):  
Jamie MacMahan ◽  
Ross Vennell ◽  
Rick Beatson ◽  
Jenna Brown ◽  
Ad Reniers

Abstract Applying a two-dimensional (2D) divergence-free (DF) interpolation to a one-person deployable unmanned underwater vehicle’s (UUV) noisy moving-vessel acoustic Doppler current profiler (MV-ADCP) measurements improves the results and increases the utility of the UUV in tidal environments. For a 3.5-h MV-ACDP simulation that spatially and temporally varies with the M2 tide, the 2D DF-estimated velocity magnitude and orientation improves by approximately 85%. Next the 2D DF method was applied to velocity data obtained from two UUVs that repeatedly performed seven 1-h survey tracks in Bear Cut Inlet, Miami, Florida. The DF method provides a more realistic and consistent representation of the ADCP measured flow field, improving magnitude and orientation estimates by approximately 25%. The improvement increases for lower flow velocities, when the ADCP measurements have low environmental signal-to-noise ratio. However, near slack tide when flow reversal occurs, the DF estimates are invalid because the flows are not steady state within the survey circuit.


Author(s):  
B. T. Vu ◽  
M. J. Verdier

A model of the wind flow conditions around Kennedy Space Center (KSC) Vehicle Assembly Building (VAB) is presented. An incompressible Navier-Stokes flow solver was used to compute the flow field around fixed Launch Complex 39 (LC-39) buildings and structures. The 3-D flow field, including velocity magnitude and velocity vectors, was established to simulate the localized wind speeds and directions at specified locations in and around LC-39 buildings and structures. The results of this study not only help explain the physical phenomena of the flow patterns around LC-39 buildings but also are useful to the Shuttle personnel. Current Operations and Maintenance Requirements and Specifications (OMRS) for vehicle transfer operations are based on empirically derived historical data, and no detailed mathematical analysis of wind conditions around LC-39 structures has ever been accomplished.


2013 ◽  
Vol 787 ◽  
pp. 495-500 ◽  
Author(s):  
Agoes Priyanto ◽  
Adi Maimun ◽  
Y.M. Ahmed ◽  
Y. Mohamed

This paper presents the rudder inflow including fully non-uniform wake on a deep drafted LNG vessel in shallow water. The Ansys Fluent v.6.2 software was used to solve Reynold Average Navier-Stokes (RANS) equations, and Icem CFD as a mesh generator. The modeling was conducted based on the B 5-88 type propeller, with a diameter (D) of 7.7 meters. The propeller was meshed using tetra unstructured mesh in a flow field based on 3-Dimension incompressible Navier-stokes solver. It was found in the propeller-to-rudder interaction that there was a slight drop of pressure at rudder leading edge of 00 rudder angle of attack (AoA). However, the dropped pressure was observed on its leading edge as the rudder angle of attack was increased to-70. The effect of increasing rudder deflection was generated by the flow around it and inflows moved over the rudder. This deflection effect continued to X/D=0.4; afterwards, a zero velocity appeared because of the flow encountered by the stagnation region.


2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Yilei He ◽  
Qiulin Qu ◽  
Ramesh K. Agarwal

This paper employs a multiobjective genetic algorithm (MOGA) to optimize the shape of a widely used wing in ground (WIG) aircraft airfoil NACA 4412 to improve its lift and drag characteristics, in particular to achieve two objectives, that is, to increase its lift and its lift to drag ratio. The commercial software ANSYS FLUENT is employed to calculate the flow field on an adaptive structured mesh generated by ANSYS ICEM software using the Reynolds-Averaged Navier-Stokes (RANS) equations in conjunction with a one equation Spalart-Allmaras (SA) turbulence model. The results show significant improvement in both the lift coefficient and lift to drag ratio of the optimized airfoil compared to the original NACA 4412 airfoil. It is demonstrated that the performance of a wing in ground (WIG) aircraft can be improved by using the optimized airfoil.


2020 ◽  
Vol 364 ◽  
pp. 152-158 ◽  
Author(s):  
Mohamad Nur Hidayat Mat ◽  
Nor Zelawati Asmuin ◽  
Md Faisal Md Basir ◽  
Marjan Goodarzi ◽  
Muhammad Faqhrurrazi Abd Rahman ◽  
...  

2021 ◽  
Vol 2129 (1) ◽  
pp. 012019
Author(s):  
Mohamad Nur Hidayat Mat ◽  
Md Faisal Md Basir ◽  
Nor Zelawati Asmuin

Abstract The critical process parameters in manufacturing dry ice blasting nozzle geometry directly related to particle jet velocity. Many studies focused on its performance without considering the noise emission due to high operating pressure. This paper, a numerical simulation study was performed using Ansys Fluent to investigate the effect of nozzle geometry of single-hose dry ice blasting on the acoustic power level. The process of modelling the two-way mass momentum and energy exchange between two phases was successfully solved iteratively in the two-way mass momentum model and the energy exchange between the two phases. It was found that the value of noise emission reaches a maximum level when the shortest convergent angle of 20° with a minimal convergent length of 50 mm and a maximum length of 300 mm is introduced. Besides, the peak value of acoustic power level swell up to 146 dB occurs at a nozzle area ratio of 20 without influencing by convergent angle and extending the divergent length highly influencing noise reduction as less than 143.5 dB for a divergent length of 700 mm.


Author(s):  
M. A. Abd Halim ◽  
N. A. R. Nik Mohd ◽  
M. N. Mohd Nasir ◽  
M. N. Dahalan

Induction system or also known as the breathing system is a sub-component of the internal combustion system that supplies clean air for the combustion process. A good design of the induction system would be able to supply the air with adequate pressure, temperature and density for the combustion process to optimizing the engine performance. The induction system has an internal flow problem with a geometry that has rapid expansion or diverging and converging sections that may lead to sudden acceleration and deceleration of flow, flow separation and cause excessive turbulent fluctuation in the system. The aerodynamic performance of these induction systems influences the pressure drop effect and thus the engine performance. Therefore, in this work, the aerodynamics of motorcycle induction systems is to be investigated for a range of Cubic Feet per Minute (CFM). A three-dimensional simulation of the flow inside a generic 4-stroke motorcycle airbox were done using Reynolds-Averaged Navier Stokes (RANS) Computational Fluid Dynamics (CFD) solver in ANSYS Fluent version 11. The simulation results are validated by an experimental study performed using a flow bench. The study shows that the difference of the validation is 1.54% in average at the total pressure outlet. A potential improvement to the system have been observed and can be done to suit motorsports applications.


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