Computational Fluid Dynamic Simulation (CFD) and Experimental Study on Wing-external Store Aerodynamic Interference of a Subsonic Fighter Aircraft

The main objective of the present work is to study the effect of an external store on a subsonic fighter aircraft. Generally most modern fighter aircrafts are designed with an external store installation. In this study, a subsonic fighter aircraft model has been manufactured using a computer numerical control machine for the purpose of studying the effect of the aerodynamic interference of the external store on the flow around the aircraft wing. A computational fluid dynamic (CFD) simulation was also carried out on the same configuration. Both the CFD and the wind tunnel testing were carried out at a Reynolds number 1.86×105 to ensure that the aerodynamic characteristic can certify that the aircraft will not be face any difficulties in its stability and controllability. Both the experiments and the simulation were carried out at the same Reynolds number in order to verify each other. In the CFD simulation, a commercial CFD code was used to simulate the interference and aerodynamic characteristics of the model. Subsequently, the model together with an external store was tested in a low speed wind tunnel with a test section sized 0.45 m×0.45 m. Measured and computed results for the two-dimensional pressure distribution were satisfactorily comparable. There is only a 19% deviation between pressure distribution measured in wind tunnel testing and the result predicted by the CFD. The result shows that the effect of the external storage is only significant on the lower surface of the wing and almost negligible on the upper surface of the wing. Aerodynamic interference due to the external store was most evident on the lower surface of the wing and almost negligible on the upper surface at a low angle of attack. In addition, the area of influence on the wing surface by the store interference increased as the airspeed increased

Experimental and simulation Studies of a Two Seater Light Aircraft

This paper presents the aerodynamic studies carried out on a three-dimensional aircraft model. The test model is a 15% scaled down from a two-seater light aircraft that close to the Malaysian made SME MD3-160 aircraft. The aircraft model is equipped with control surfaces such as flaps, aileron, rudder and elevator and it is designed for pressure measurement testing and direct force measurement using a 6-components balance system. This aircraft model has been tested at two different low speed tunnels, at Universiti Teknologi Malaysia tunnel sized 1.5 x 2.0 meter2 test section, and at Institute Aerodynamic Research, National Research Council of Canada sized 3 x 2 meter2 tunnel. The speed during testing at UTM and IAR/NRC tunnels was up to 70 meter/second, which is corresponds to Reynolds numbers of 1.3 x 106.The longitudinal and lateral directional aerodynamic characteristics of the aircraft such as coefficients of pressure, forces (lift, drag, side) and moments (roll, pitch and yaw) have been experimentally measured either using direct force measurement or pressure measurement method. The data reduction methods include the strut support interference factor using dummy image and the blockage correction have been applied in this project. The results showed that for the undeployed flap configuration, the stalling angle of this aircraft is 160 at CLMax = 1.05 measured by UTM - LST, compared to CLMax =1.09 at stalling angle 150 by IAR- NRC. Beside the experimental study, simulation also be performed by using a commercial Computational Fluid Dynamics (CFD) code, FLUENT Version 5.3. Experimental works at UTM and IAR – NRC tunnel show that the aerodynamic characteristics of this light aircraft are in a good agreement with each other. Simultaneously, the aerodynamic forces obtained from experimental works and CFD simulations have been compared. The results proved that they are agreeable especially at a low angle of attack

The comparison of various gas turbine inlet aircooling methods for various ambient condition trough energy and exergy analysis

The strong influence of climate conditions on gas turbine behavior is well known. During the summer season the output of gas turbines falls to a value that is less than the rated output under high temperature conditions. Cooling the turbine inlet air can increase output power considerably, because cooled air is dense, giving the turbine a higher mass flow rate and resulting in increased turbine output and efficiency. This study is to use the energy and exergy analysis method to evaluate the air cooling method used for enhancing the gas turbine power plant. In addition, the effect of inlet air cooling method on the output power, exergy efficiency and exergy destruction have been analyzed. Also at the end of the paper the comparison of two mentioned methods has been investigated

Numerical investigation of rectangular twisted hole on film cooling for gas turbine blades

This paper investigates a new method of film cooling using swirling coolant flow through a rectangular twisted film cooling holes with spirally corrugated tube. Two different air flows with different in temperatures were used in this study. Throughout the investigation, blowing ratio was varied from 0.5 to 2.0 with several configuration of rectangular twisted angle of 0°, 90°, 180°, 270° and 360°. The results of cooling effectiveness obtained were compared against a standard untwisted tube. Results show that the overall thermal effectiveness improved significantly when the temperature difference between the air flows is at 25 degrees. Such improvement is supported by heat transfer enhancement that obtained from 19% to 57%. Based on the findings, the study concludes that using a simple geometry of film cooling hole with specific twisted configuration may result to improve the convective heat transfer coefficient

Numerical studies on unsteady helicopter main-rotor-hub assembly wake

The objective of this research is to quantify viscous unsteady flow phenomenon observed behind a helicopter main-rotor-hub assembly, as the part is believed to be a major contributor to tail shake phenomenon. In this numerical investigation, the aerodynamic flow field was computed using Large Eddy Simulation equations. To simulate the wake dynamics, Multiple Reference Frames (MRF) method was applied to rotate the main-rotor-hub assembly. Simulations were also run with fairing installed on the main-rotor-hub assembly. The results concluded that fairing does significantly alter the wake's structures and help to reduce aerodynamic drag to about 5% lesser. In addition, analysis from power spectral density (PSD) had successfully quantified the frequencies of this unsteady wake, as well the strength of their amplitudes. It had also manifested a significant growth of wake amplitude to 109% when the rotor rotation was increased from 1400 rpm to 1600 rpm, implying a strong correlation between the flow unsteadiness and the speed of rotor rotation. These findings are alleged to be valuable for future research and development in the rotorcraft industry

Computational Fluid Dynamic Simulation (CFD) and Experimental Study on Wing-external Store Aerodynamic Interference of subsonic Fighter Aircraf

The main objective of the present work is to study the effect of an external store to a subsonic fighter aircraft. Generally most modern fighter aircraft is designed with an external store installation. In this project a subsonic fighter aircraft model has been manufactured using a computer numerical control machine for the purpose of studying the effect of the external store aerodynamic interference on the flow around the aircraft wing. A computational fluid dynamic (CFD) and wind tunnel testing experiments have been carried out to ensure the aerodynamic characteristic of the model then certified the aircraft will not facing any difficulties in stability and controllability. In the CFD experiment, commercial CFD code is used to simulate the interference and aerodynamic characteristics of the model. Subsequently, the model together with an external store was tested in a low speed wind tunnel with test section sized 0.45 m×0.45 m. Result in the two-dimensional pressure distribution obtained by both experiments are comparable. There is only 12% deviation in pressure distribution found in wind tunnel testing compared to the result predicted by the CFD. The result shows that the effect of the external storage is only significant at the lower surface of the wing and almost negligible at the upper surface of the wing. Aerodynamic interference is due to the external storage were mostly evidence on a lower surface of the wing and almost negligible on the upper surface at low angle of attack. In addition, the area of influence on the wing surface by store interference increased as the airspeed increase

Estimation of Aerodynamic Characteristics of a Light Aircraft

This paper presents the aerodynamic estimation carried out on a three-dimensional aircraft model by conducting wind tunnel tests and Computational Fluid Dynamics (CFD) simulation. The test model is a 15% scaled down from a two-seater light aircraft that is closed to the Malaysian made SME MD3-160 aircraft. This aircraft model has been tested at two different low speed tunnels, namely at Universiti Teknologi Malaysia’s tunnel (UTM-LST) test section sized of 2.0 x 1.5 m2, and at Institute Aerodynamic Research, National Research Council of Canada (IAR-NRC) sized 3.0 x 2.0 m2 tunnel. The speed during testing at UTM-LST and IAR-NRC tunnels was up to 70 m/s, which corresponds to Reynolds Number of 1.3 x 106. The longitudinal and lateral directional aerodynamic characteristics of the aircraft such as coefficients of pressure, forces (lift, drag and side force) and moments (roll, pitch and yaw moment) had been experimentally measured either using direct force measurement or pressure measurement method. The data reduction methods included the strut support interference factor using dummy image and the blockage correction had been applied in this wind tunnel tests. On top of the experimental study, simulation was also performed using a commercial CFD code, FLUENT. Experimental works at UTM-LST and IAR–NRC tunnel showed that the aerodynamic characteristics of this light aircraft were in good agreement with each other. Simultaneously, the aerodynamic forces obtained from the experimental works and CFD simulations had been compared. The results proved that they were agreeable especially at a low angle of attack

Computational Fluid Dynamic Simulation (CFD) and Experimental Study on Wing-external Store Aerodynamic Interference

The main objective of the present work is to study the effect of an external store to a subsonic fighter aircraft. Generally most modern fighter aircraft is designed with an external store installation. In this project a subsonic fighter aircraft model has been manufactured using a computer numerical control machine for the purpose of studying the effect of the external store aerodynamic interference on the flow around the aircraft wing. A computational fluid dynamic (CFD) and wind tunnel testing experiments have been carried out to ensure the aerodynamic characteristic of the model then certified the aircraft will not facing any difficulties in stability and controllability. In the CFD experiment, commercial CFD code is used to simulate the interference and aerodynamic characteristics of the model. Subsequently, the model together with an external store was tested in a low speed wind tunnel with test section sized 0.45 m×0.45 m. Result in the two-dimensional pressure distribution obtained by both experiments are comparable. There is only 12% deviation in pressure distribution found in wind tunnel testing compared to the result predicted by the CFD. The result shows that the effect of the external storage is only significant at the lower surface of the wing and almost negligible at the upper surface of the wing. Aerodynamic interference is due to the external storage were mostly evidence on a lower surface of the wing and almost negligible on the upper surface at low angle of attack. In addition, the area of influence on the wing surface by store interference increased as the airspeed increase.

Combustor aerodynamics

This book describes the new innovation of gas turbine swirler. The novel swirler is a multiple entry swirler which allows the swirl number to vary on the same value of Reynolds number, by regulating the ratio between the axial and tangential flow momentum. Three–dimensional turbulence and isothermal flow characteristics of an abrupt combustor model with different type of swirler (axial, radial and multiple inlet) were simulated with Reynolds–Averaged Navier–Stokes (RANS) using ANSYS Fluent 12 software. Results of the different turbulence models used in swirling flow were reviewed and compared. The different swirler’ aerodynamic performance was investigated through Computational Fluid Dynamics (CFD) simulations. The aerodynamics performance includes shape and size of the Central Recirculation Zone (CRZ), turbulence intensity and pressure losses. It was found that the size of then CRZ and turbulence strength is directly proportional to the tangential axial air flow rate ratio. Therefore, proper selection of a swirler is needed to enhance combustor performance and to reduce exhaust emissions