Wirachman Wisnoe

Numerical investigation of temperature distribution in a diffuser equipped with helical tape

The effect of helical tape inside a conical diffuser on the temperature distribution is examined. In the present paper helical tape with different pitches (20 mm, 25 mm, and 30 mm) and different tape geometries (H=10mm, 15mm) with the same pitch (30mm) are studied in order to observe their effect on the temperature distribution. The length of diffuser, inlet diameter, outlet diameter, and the divergent angle are kept constant for all pitches of tape. The analysis is carried out using CFD software using k-ε turbulence model. The results show that small pitch gives better distribution of temperature, and increasing tape height improves the distribution in the radial-tangential direction.

Experimental investigation on the effect of conical valve shape and swirl generator to the performance of Ranque-Hilsch Vortex Tube

Temperature at cold outlet, cold mass fraction and isentropic efficiency in the Ranque-Hilsch Vortex Tube (RHVT) are experimentally measured and derived. For the experiment, different pressures (absolute) (between 290 to 800 kPa) were applied as source, 3 types of swirl generator and 3 shapes of conical valve were used. The lowest temperature obtained during the experiment was -11.6 for a cold mass fraction (μ_c = 0.947) which gave the highest isentropic efficiency (η_is= 0.336) at source pressure of 790.2 kPa. However, the highest cold mass fraction (μ_c = 1.024) was given by source pressure of 790.2 kPa with isentropic efficiency (η_is) of 0.042 and the cold temperature was 20°C.

Investigation on aerodynamic characteristics of baseline-II E-2 blended wing-body aircraft with canard via computational simulation

Previous wind tunnel test has proven the improved aerodynamic charasteristics of Baseline-II E-2 Blended Wing-Body (BWB) aircraft studied in Universiti Teknologi Mara. The E-2 is a version of Baseline-II BWB with modified outer wing and larger canard, solely-designed to gain favourable longitudinal static stability during flight. This paper highlights some results from current investigation on the said aircraft via computational fluid dynamics simulation as a mean to validate the wind tunnel test results. The simulation is conducted based on standard one–equation turbulence, Spalart-Allmaras model with polyhedral mesh. The ambience of the flight simulation is made based on similar ambience of wind tunnel test. The simulation shows lift, drag and moment results to be near the values found in wind tunnel test but only within angles of attack where the lift change is linear. Beyond the linear region, clear differences between computational simulation and wind tunnel test results are observed. It is recommend...

Static stability of Baseline-II blended wing- body aircraft at low subsonic speed: Investigation via computational fluid dynamics simulation

A study of the effect of canard to Baseline-II blended wing-body aircraft is presented here with emphasis on investigating contributions of canards various setting angle to aerodynamic parameters and longitudinal static stability. A computational fluid dynamic (CFD) simulation has been conducted at low subsonic speed to collect aerodynamic data and found that its aerodynamic trend is similar to many BWB aircraft and consistent to previous studies conducted in UiTM. Canard setting angle affects the value of lift-at-zero incidence of a BWB aircraft, although fairly small for current canard size that it is not adequate to produce positive pitching moment-at-zero lift. Baseline-II is partially, statically stable in longitudinal motion because of negative moment change w.r.t. lift change but it has equilibrium incidence angle that only produces negative lift. Larger canard and/or modification to Baseline-II wing-body are needed to overcome this flaw. The location of new reference point provides ‘comfortable’ static margin. Data and mathematical characteristic obtained from BL-IIA SP CFD simulation is comparable to those from wind tunnel experiment and both show satisfactory-to-good correlation to theoretical calculations.

A study about the split drag flaps deflections to directional motion of UiTM's blended wing body aircraft based on computational fluid dynamics simulation

This paper discusses on the split drag flaps to the yawing motion of BWB aircraft. This study used split drag flaps instead of vertical tail and rudder with the intention to generate yawing moment. These features are installed near the tips of the wing. Yawing moment is generated by the combination of side and drag forces which are produced upon the split drag flaps deflection. This study is carried out using Computational Fluid Dynamics (CFD) approach and applied to low subsonic speed (0.1 Mach number) with various sideslip angles (β) and total flaps deflections (δT). For this research, the split drag flaps deflections are varied up to ±30°. Data in terms of dimensionless coefficient such as drag coefficient (CD), side coefficient (CS) and yawing moment coefficient (Cn) were used to observe the effect of the split drag flaps. From the simulation results, these split drag flaps are proven to be effective from ±15° deflections or 30° total deflections.

The Effect of Canard on Aerodynamics of Blended Wing Body

This paper describes the wind tunnel testing of a Blended Wing Body (BWB) with rectangular canards and twisted wing (Baseline II E2 configuration) developed in Universiti Teknologi MARA (UiTM). The experiment work was carried out in UiTM low speed wind tunnel using 1:6 scaled model of BWB at Mach 0.1. The testing is conducted for canard’s deflection angle between 0° to +20. The results show by adding the canard surface to the BWB’s body, at 12 degree and higher angles of attack,α there will be a slight increment in lift. Maximum lift-to-drag ratio decreases with increasing canard surface deflection. Also, by adding the canard surface, the value of moment at zero lift,CM,0 is increased.

Design and analysis for development of a wing box static test rig

Airplanes are designed to stay aloft with the help of wings on both sides. In operation at cruising speed, the wings are subjected to load as much as the weight of the whole aircraft. However during maneuver, the wings are subjected much higher load and stress and this stress should be sustained by the wings within its limit load without causing permanent deformation to the structure. In order to assess how much stress the wings are subjected to, the wings should be tested on ground which is called static test. To proof that a design is good, a numerical analysis should be verified by experimental analysis. The static test can be done in a test rig. The test rig however should be much stronger than the object to be tested. Therefore, in this paper the design parameter such design configuration, is one of the parameters to be studied in the development of the test rig. In this paper, a finite element analysis was done on the 2D model of the test rig in order to verify the parametric design. Using ANSYS Workbench V12.1, an alteration was made to compare if the initial design was good or can be made better.

Experimental Investigation of Orifice Diameter, Swirl Generator and Conical Valve Shape to the Cooling Performance of Ranque-Hilsch Vortex Tube

This paper is about experimental investigation of the orifice diameter, swirl generator and conical valve shape influence the cooling performance of Ranque-Hilsch vortex tube. From the experiment, its shows that conical valve shape has smallest effect on cooling performance (0.124) of the Ranque-Hilsch vortex tube. It also revealed that swirl generator gave the greatest (0.336) effects to the cooling performance of Ranque-Hilsch vortex tube and have the highest range of difference cooling performance (0.027 to 0.229) compare to conical valve shape (0.073 to 0.087) and orifice diameter (0.009 to 0.012).

Yaw Stability Analysis for UiTM's BWB Baseline-II UAV E-4

This paper presents a study about yaw stability analysis for UiTMs Blended-Wing-Body (BWB) Baseline-II E-4. This aircraft is equipped with split drag flaps in order to perform directional motion. One of the split drag flaps will be deflected to generate yawing moment. This yawing moment is generated through the drag that is produced upon deflection of flaps. The study was carried out using Computational Fluid Dynamics (CFD) for various sideslip angles (β) and various flaps deflection angle (δT). The simulation was conducted at 0.1 Mach number (35 m/s) and results in terms of coefficient such yawing and rolling moment are tabulated in order to determine the stability of the aircraft. The result reveals that the aircraft is directionally unstable. This is as expected because the aircraft does not have any vertical tail configuration to provide the yawing moment. However, high deflection of split flaps can still generate adequate restoring moment for the aircraft.

Flow Characteristics of a Servco Fume Cupboard

A fume cupboard is equipment used to carry out chemical reaction process in its working chamber. A suction fan takes air or gas from the working chamber and releases it outside. When the air or gas is flowing from the inlet to the outlet, some recirculation zones may be formed depending on the internal shape design of the fume cupboard. This recirculation zone may create back flow that can be the cause of leakage. Leakage happens when airborne contaminants escape through inlet of the fume cupboard to the user breathing zone and the surrounding air in the room. To have a good fume cupboard, the recirculation zone needs to be minimised. In this paper, the flow characteristic of a Servco fume cupboard will be presented as a result of computational fluid dynamics (CFD) simulation using κ-ω turbulence model. The results are presented in terms of velocity components at different cross sections of the fume cupboard.