DESAIN NOSEL ROKET CAIR RCX250 MENGGUNAKAN METODE PARABOLIK DENGAN MODIFIKASI SUDUT EKSPANSI

ABSTRACTThe present research is conducted to design the optimum nozzles for RCX250 engine, that is designed to produce maximum thrust of 250 kgf with combination of LOX and Kerosene as its propellant. The new nozzles were determined to be parabolic nozzle, with conical nozzle as its comparison. The parabolic nozzle was designed using Thrust Optimized Parabolic (TOP) method invented by G.V.R.Rao. TOP nozzle design method is performed by approximating a Thrust Optimized Contoured (TOC) Nozzle using parabolic equation. The method would result more efficient nozzle than conical or ideal bell nozzle. Further, the parabolic nozzle were modified in its initial and exit angle to create uniform velocities distribution at nozzle exit. A Computational Fluid Dynamics Method (CFD) is used to simulate the nozzle designs. The simulation was carried out in axis-symmetric condition using commercial CFD software. The simulation results show that MOD 1 nozzle, with initial angle (?N) 26 deg and exit angle (?e) 12 deg, gives maximum thrust, which is 4.67 % higher than reference conical nozzle.ABSTRAKPenelitian ini ditujukan untuk mendesain nosel optimum untuk enjin RCX250 yang didesain mampu menghasilkan gaya dorong maksimum 250 kgf dengan propelan pasangan LOX dan kerosen. Nosel baru yang didesain berupa nosel bell/parabolik, yang nantinya akan dibandingkan dengan nosel cone. Nosel parabolic didesain dengan metode Thrust Optimized Parabolic (TOP), yang ditemukan oleh G.V.R.Rao. Metode desain TOP Nosel dilakukan dengan melakukan aproksimasi dari nosel Thrust Optimized Contour (TOC) menggunakan persamaan parabolik. Metode ini akan menghasilkan nosel yang lebih efisien dibandingkan dengan nosel cone ataupun ideal bell. Lebih jauh lagi, nosel parabolik yang telah didesain akan dimodifikasi pada sudut ekspansi awal dan sudut exit untuk menghasilkan distribusi kecepatan yang seragam pada bagian exit. Metode Dinamika Fluida Komputasional (CFD) digunakan untuk mensimulasikan 8 model nosel parabolik hasil desain. Simulasi dilakukan pada kondisi axis-symmetric menggunakan software CFD komersial. Dari hasil simulasi, dapat diketahui bahwa nosel MOD 1 dengan sudut inisial (?N) 26 derajat dan sudut exit (?e) 12 derajat menunjukkan hasil thrust paling tinggi, 4.67 % lebih tinggi dari thrust nosel cone acuan.Hal. 8-17:ilus.; 30 c

Perancangan Kontur Nozzle Supersonik untuk Terowongan Angin

Hlm. 577-58

Model Predictive Control in Hardware in the Loop Simulation for the OnBoard Attitude Determination Control System

Rocket flight tests invariably serve a purpose, one of which involves area monitoring or aerial photography. Consequently, the rocket necessitates the installation of a camera that remains consistently oriented toward the Earth's surface throughout its trajectory. Thus, ensuring the rocket's stability and preventing any rotation becomes imperative. To achieve this, the Onboard Attitude Determination Control System (OADCS) was researched and developed, fully controlled by NI myRIO with Labview as the programming language, ensures the rocket's attitude control and maintains a rolling angle of 0 degrees during flight. The MyRIO oversees the retrieval of attitude and position data from the X-Plane flight simulator, offering feedback through actuator control. The development of the OADCS proceeded incrementally through stages utilizing the Software in the Loop Simulation (SILS) and Hardware in the Loop Simulation (HILS) techniques, to ensure the verification of the system's functionality before its application to the rocket for real flight testing. In the OADCS control scheme, Model Predictive Control (MPC) is chosen, and it is compared with a PID controller to serve as a benchmark for processing speed. Because the rocket's flight time is short and its speeds of up to Mach 4. The simulation results indicate that MPC can halt the rocket's rotation 12 times more rapidly than PID control. Additionally, the MPC's ability to maintain a zero-degree rotation can persist throughout the rocket's flight time. Employing SILS and HILS enhances the OADCS rocket development process by incorporating MPC, which holds promise for application in real rockets