Kamil Abdullah

Experimental Investigations on Aero-Thermal Interaction of Film Cooling Airs Ejected From Multiple Holes: Shallow Hole Angle

This paper presents thermal and aerodynamics investigations of multiple cooling holes with shallow hole angle. Three test models have been considered namely TMA, TMB and TMG. TMB is acting as the baseline test model having 35° hole angle cooling holes. The other two test models; TMA and TMG, have a shallow hole angle of 20° with different lateral pitch distance of 6D and 3D respectively. Total of twenty conventional cylindrical cooling holes have been arranged to form a five times four matrix. All three test models have been considered in the thermal investigations with only the shallow hole angle test models have been considered for the aerodynamics investigation. The film cooling effectiveness has been measured by means of infrared thermography while 3D-LDV has been utilized for the flowfield measurements. The measurements were carried out at single Reynolds number base on the hole diameter of 6200 at three different blowing ratios of 0.5, 1.0 and 2.0. All three blowing ratios have been considered in the thermal investigations with only the latter two blowing ratios were considered in the aerodynamics investigation. The results are presented in the form of contour plot of various variables including film cooling effectiveness, normalized u, v, and w velocities, normalized root mean square of u velocity and Reynolds stress tensors. Distribution of laterally average film cooling effectiveness along the x-axis are also presented, showing that the 20° hole angle cooling holes provide a very promising results particularly at high blowing ratio. The velocities contours clearly capture the flow structure of the film cooling jets, along with the effects of blowing ratios and lateral pitch on the flowfield.Copyright

Effects of Blowing Ratio on Multiple Shallow Angle Film Cooling Holes

This paper presents the investigation on the effects of the blowing ratio of multiple shallow angle film cooling holes. Multiple film cooling holes having a shallow hole angle (θ = 20°), arranged to perform in-line hole configuration has been considered in the present study. The investigation focuses on the effects of high blowing ratio of the film cooling effectiveness which have been carried out at ReD = 3100 and BR = 2.0, 3.0 and 4.0. The experiments make use of the IR camera in capturing the surface temperature to determine the film cooling effectiveness. The contours of the film cooling effectiveness distribution together with plots on laterally average film cooling effectiveness along the x/D are presented. The discussions have been made with a support of the temperature field captured at x/D = 3, 13, 23, and 33. The results clearly show the benefit of the employment of shallow hole angle (θ = 20°) at high blowing ratio which is much more superior in comparison to the common hole configuration (θ = 35°).

Experimental and Numerical Investigation on Flowfield of Film Cooling from Multiple Holes

This paper presents the experimental and numerical investigation on flowfield of multiple film cooling hole focuses on shallow hole angle at 20°. An in-line hole configuration consist of 20 cooling holes have been considered in the present study. Investigation have been carried out at ReD=6,200 and BR=1.0 with the experimental investigation involves 3D-LDV device to capture the experimental velocity flowfield. The numerical investigation was carried out through RANS analyses with the employment of shear stress transport turbulent model. The results highlights the benefit of shallow hole angle configuration with good agreements have been achieved between the experimental and the numerical results.

Computational Fluid Dynamics Simulation on Blood Velocity and Vorticity of Venous Valve Behaviour

In this work, a computational fluid dynamics (CFD) is used to analyze the effect of different opening between two valves of a normal popliteal vein. This study was focusing on the velocity and also vorticity of blood along the popliteal vein distribution. Based on the observation and analysis of the data, the different size of orifice between the first valve and second valve influencing the velocity and vorticity of the blood flow. The rotational motion of blood particle at the same spot will increasing the probability of blood accumulating which helping in development of thrombus. The effect of the irregularities in the blood flow will cause valve insufficiency that will lead to various disease related to venous vessel such as heart attack, deep vein thrombosis (DVT), pulmonary embolism (PE)and the worst is death. A series of experiment has been conducted by changing the size of valve orifice for the first and second valve along the vein distribution. The result of the CFD simulation shows a significant result of blood flow in term of velocity and vorticity.

Numerical study of flow past a solid sphere at high Reynolds number

The present study gives a detail description of separation flow and its effect under high Reynolds number. The unsteady three dimensional flow simulation around sphere using numerical simulation computational fluid dynamics for high Reynolds number between 300 000 < Re < 600 000 is discussed. The separation angle and drag coefficient are also presented. The results show that the increasing Reynolds number affecting the formation of vortex shedding, separation point and drag coefficient. The agreement was good, confirming the reliability of the predicted data from computational fluid dynamic in flow analysis around sphere at high Reynolds number.

Effect of ground proximity on the flow over STOL CH750 multi-element airfoil

The paper presents the influence of ground distance on aerodynamic characteristics of the flow over short take-off and landing STOL CH750 aircraft multi-element airfoil at various flap angle of deflection. The angle of attack is kept constant throughout the computations. ANSYS is used for the grid generation and the computational calculation. Further investigation suggests the best range of deflection angle where the aerodynamic performance of the airfoil increases in the presence of ground. Furthermore, a cushion of high-pressure air region between the airfoil pressure side and the ground surface also emerges.

Pressure recovery performance of 2-D turning diffuser by varying area ratios and inflow Reynolds numbers

The paper aims to investigate the effects of varying area ratio, AR = 1.2 and 4.0 and inflow Reynolds number, Rein = 5.478 x 104 - 1.547 x105 on the performance of 90o twodimensional turning diffuser. The optimum configuration area ratio and Rein to produce good pressure recovery is determined. The rig was developed to produce fully developed entrance flow by adopting arrangement of mesh net and sufficient hydrodynamic entrance length, Lh, turb= 28 Dh. Digital manometer was used to measure the inlet and outlet static pressures and Particle Image Velocimetry (PIV) to visualize the flow structure. The present results were compared with empirical solution of Asymptotic Computational Fluid Dynamics (ACFD) results to give acceptable deviation of ±7.4%. The AR=4.0 produces pressure recovery 20% more than AR=1.2 when applies low Rein<1.40 x 105. However, it is subjected to severe flow separation and circulation at Rein>1.40 x 105 that considerably disturbs the recovery. Therefore, turning diffuser of AR=1.2 is optimum applied for high Rein>1.40 x 105.

Comparative study of Roe, RHLL and Rusanov fluxes for shock-capturing schemes

Computational Fluid Dynamics provides approximations through iterative calculation to simulate and predict the solution and has been extensively used in the investigation of shockwave. The paper aims to compare the capability of Roe, RHLL and Rusanov flux function in capturing shock phenomena. Two cases have been presented in the paper; one-dimensional case and two-dimensional cases. In general, all the considered flux function capable to capture general pattern of the shockwave phenomena. However, the results shows that it is important to pay great attention to the diffusive component of the fluxes. Strong diffusive component of the flux will helps to bring stability in the solution but at the same time prevent the fluxes to capture small changes of the fluid properties.

Numerical study of canister filters with alternatives filter cap configurations

Air filtration system and filter play an important role in getting a good quality air into turbo machinery such as gas turbine. The filtration system and filter has improved the quality of air and protect the gas turbine part from contaminants which could bring damage. During separation of contaminants from the air, pressure drop cannot be avoided but it can be minimized thus helps to reduce the intake losses of the engine [1]. This study is focused on the configuration of the filter in order to obtain the minimal pressure drop along the filter. The configuration used is the basic filter geometry provided by Salutary Avenue Manufacturing Sdn Bhd. and two modified canister filter cap which is designed based on the basic filter model. The geometries of the filter are generated by using SOLIDWORKS software and Computational Fluid Dynamics (CFD) software is used to analyse and simulates the flow through the filter. In this study, the parameters of the inlet velocity are 0.032 m/s, 0.063 m/s, 0.094 m/s and 0.126 m/s. The total pressure drop produce by basic, modified filter 1 and 2 is 292.3 Pa, 251.11 Pa and 274.7 Pa. The pressure drop reduction for the modified filter 1 is 41.19 Pa and 14.1% lower compared to basic filter and the pressure drop reduction for modified filter 2 is 17.6 Pa and 6.02% lower compared to the basic filter. The pressure drops for the basic filter are slightly different with the Salutary Avenue filter due to limited data and experiment details. CFD software are very reliable in running a simulation rather than produces the prototypes and conduct the experiment thus reducing overall time and cost in this study.

Parametric Study on Geometrical Arrangement of Sister Hole

Modern gas turbines require a sophisticated cooling scheme to remove the heat from its component to ensure it durability. One of the common techniques applied in the cooling scheme is film cooling The present study focuses numerical investigation of an sister cooling hole design. The investigations make use of commercial CFD software, ANSYS CFX. The numerical investigations have been carried out at Reynolds number, Re = 21,000 involving three differens blowing ratios, BR = 0.5, 1.0, and 1.5. Four different cases have been considered; STA, STB STC and SH. The results show promising improvement in terms of film cooling effectiveness with the implementation of sister holes in certain geometrical arrangements.