scholarly journals JUSTIFIKASI CFD KEDALAMAN GROOVE BAN PADA PROSES PERAWATAN HARIAN PESAWAT B737-800 AKIBAT HYDROPLANING (B737-800 TIRE GROOVE DEPTH CFD JUSTIFICATION ON ITS DAILY MAINTENANCE PROCESS DUE TO HYDROPLANING)

2017 ◽  
Vol 15 (1) ◽  
pp. 29 ◽  
Author(s):  
Vicky Wuwung ◽  
Nelli Anggreyni ◽  
Valeri Maria Hitoyo ◽  
Carolus Bintoro

As a reference in daily maintenace process of Boeing 737-800 air plane, The tire groove depth influence justification which is moving on the contaminated runway that could be potential to hydroplaning phenomenon must be reviewed. Tire groove is a pattern on the tire surface that has a function to flow the water in front of the tire to the aft of the tire smoothly through the bottom of the tire. This mechanism let the tire less of a lift force that can be meant as a hydroplaning prevention. To understand hydroplaning phenomenon and groove depth tire influence, a numerical simulation is performed by using a CFD software Numeca Fine/Marine. This simulation is 3D, unsteady fluid dynamic simulation, with an assumption a rigid body tire at a short time after the airplane touch down to the runway (after skidding process) with velocity V = 62.27 m/s. The contaminated runway is modelled as a pool water (flood) on the flat surface runway with its height of 2.54 mm. Numerical simulation on this B 737-800 tire result shows that a hydroplaning phenomenon will happen for tire with groove depth less than 0.4”. This concludes that a lesser groove depth of tire will reduce a tire groove cross sectional area, and will increase a compression force in the bottom at the front of the tire, that will result in increasing a lift force to the tire and finally increasing a chance to hydroplaning process. From this result, furthermore, the influence of this groove depth of B 737-800 tire variation that is run on a contaminated runway can be used as a reference on B 737-800 tire daily maintenance. AbstrakGroove atau ‘kembang” pada ban pesawat merupakan sarana untuk mengalirkan air dari bagian depan menuju bagian belakang melalui bagian bawah ban, tanpa mengangkat ban sehingga dapat mencegah terjadinya hydroplaning. Sehingga, pengaruh nilai kedalaman groove terhadap gaya angkat pada ban pesawat B737-800 yang bergerak di landasan dengan genangan air perlu dijustifikasi dalam proses perawatan harian. Penelitian ini menyimulasikan proses mengalirnya air pada bagian bawah ban dengan menggunakan simulasi numerik (CFD Numeca Fine/Marine) 3-D unsteady sebagai metode untuk menjustifikasi pengaruh groove. Simulasi dilakukan untuk kondisi gerakan ban pesawat pada saat proses landing (V = 62,275 m/s) beberapa saat setelah touch down (setelah skidding) dengan ban pesawat dianggap rigid body sebagai kondisi batas. Selanjutnya tinggi genangan air dipilih pada saat runway dinyatakan dalam kondisi flood (tinggi genangan air = 2,54mm). Simulasi tersebut menampilkan hasil perhitungan ban pesawat Boeing 737-800, dengan hydroplaning mulai terjadi ketika kedalaman groove ban berada dibawah 0,4 inch. Hal ini menunjukkan bahwa semakin kecil kedalaman groove, maka semakin kecil luas penampang groove dan semakin besar gaya kompresi yang terjadi pada bagian bawah ban dan semakin memperbesar kemungkinan terjadinya fenomena hydroplaning. Dengan diketahuinya hasil dari simulasi tersebut, maka hasil penelitian ini dapat digunakan sebagai masukan bagi proses maintenance harian pesawat B737-800 dan mampu memberikan suatu hal baru dalam pembelajaran khususnya mengenai fenomena hydroplaning.

Author(s):  
Ramlala P. Sinha

A solution of the highly complex unsteady compressible flow field inside a cylindrical resonance tube has been obtained numerically, assuming one dimensional, viscous, and heat conducting flow, by solving the appropriate fluid dynamic and energy equations. The resonance tube is approximated by a right circular cylinder closed at one end with a piston oscillating at resonant frequency at the other end. An iterative implicit finite difference scheme is employed to obtain the solution. The scheme permits arbitrary boundary conditions at the piston and the end wall and allows assumptions for transport properties. For the example considered herein, the solution predicts a rise of 95°F in the mean end wall temperature, from 60°F to 155°F, in 14.313 milliseconds which is in good agreement with the experimentally observed values. The solution would also be valid for tapered tubes if the variations in the cross-sectional area are small. In successfully predicting the resonance tube results, an innovative simple but stable solution of unsteady fluid dynamic and energy equations is provided here for wide ranging research, development, and industrial applications in solving a variety of complex fluid flow heat transfer problems. The method is directly applicable to pulsed or pulsating flow and wave motion thermal energy transport, fluid-structure interaction heat transfer enhancement, and fluidic pyrotechnic initiation devices.


2012 ◽  
Vol 490-495 ◽  
pp. 2156-2159
Author(s):  
Wu Gang Li

In order to find the principal axes of inertia and calculate their moment of inertia to any plane homogeneous rigid body for calculating easily the moment of inertia to any axis of this rigid body, the principal axes could be found and their moment of inertia could be calculated automatically by using the reading-image of MATLAB to read the image messages about the flat surface of the rigid body and by the procedures which ware made according to the logic relation about the principal axis and the moment of inertia of the rigid body. Applying this method in a homogeneous cube, a result was acquired, error of which is small compared with the theoretical value. So this method is reliable, convenient and practical


2012 ◽  
Vol 58 (5) ◽  
pp. 57-67 ◽  
Author(s):  
Hua QIU ◽  
Yoshiyuki IEMOTO ◽  
Shuichi TANOUE ◽  
Hideyuki UEMATSU

Author(s):  
Ang Li ◽  
Jun Chen ◽  
Yangfan Liu ◽  
Stuart Bolton ◽  
Patricia Davies

Abstract In recent years, the bladeless fan that does not have visible impellers have been widely applied in household appliances. Since the customers are particularly sensitive to noise and the strength of wind generated by the fan, the aerodynamic and acoustic performances of the fan need to be accurately characterized in the design stage. In this study, computational fluid dynamic (CFD) and computational aeroacoustics (CAA) are applied to investigate the performances of different designs of a bladeless fan model. The influence of four parameters, namely the airfoil selection for cross-section of the wind channel, the slit width, the height of cross-section and the location of the slit, is investigated. The results indicate the streamwise air velocity increases significantly by narrowing the outlet, but the noise level increases simultaneously. In addition, the generated noise increases while the height of fan cross-section increases, and a 4mm height of the cross section is optimal for aerodynamic performance. When the slit is closer to the location of maximum thickness, the performances of the bladeless fan increases. Moreover, the performance is not changed significantly by changing the cross-sectional profile. Finally, the optimal geometric parameters are identified to guide the future design of the bladeless fan.


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