VENTURI NOSEL DESIGN OPTIMZATION FOR BIOGAS COMBUSTION THROUGH MODELLINGAND EXPERIMENT

• Main Author: Ketut Lasmi, Ni
• Format: Dissertations
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/33864
• Institution: Institut Teknologi Bandung

The limited availability of fossil fuel energy resource is the reason for the need for other alternative resources. Biogas is one of the renewable energy resources that can be used as a fuel for small-scale power plants. The topic of biogas utilization as a fuel in electric generators is proposed to reduce the dependence on gasoline fuel which until now is still the main fuel in generating small scale electricity using generators. The initial experiment by replacing gasoline fuel with biogas directly on the generator yielded that the generator was not operating properly. In this study, a modification of the venturi nozzle was conducted. The venturi is located on the biogas feeder in the carburetor chamber where the biogas is mixed with the combustion air. The modification of the venturi is made possible by cutting the edge of the nozzle as to have a truncated diagonal-end shape. The modified venture is operated setting openings of air pipe in the venturi carburetor chamber. The experimental results show that the generator produced electric power of 473.00 Watts to 807.40 Watts. The electric generator with biogas fuel (without gasoline) that used the modified nozzles with a diameter of 0.30 cm to 0.65 cm, resulted in efficiency of electrical power from 4.02% to 5.46% respectively, indicating the achievability of the desired efficiency. The success of experiment requires a scientific study. This study was conducted based on the fluid dynamics simulations using CFD software in two-dimensional (2D) and three-dimensional (3D) space for turbulent flow, for flat (original) and truncated nozzles. The simulation results provide validation that the success of electricity production from the experiment is realized by the biogas flow in the venturi carburetor chamber which directly leads to the fuel cylinder. On the other hand, the non-operational condition of the generator occurring is justified by the biogas flow coming into the air inlet. Openings angle settings in space of air were simulated at various angles. At certain angles, in this case 30?, 45?, and 60?, backflow and forward flow events were generated. The results of CFD simulations provide confirmation of electricity production events, both for generators that operate properly and those that do not. This dissertation describes that technological studies of complex fluid phenomena from experimental results can be revealed by modeling of complex flow dynamics using CFD software in the form of numerical estimates of three-dimensional speed variable values, pressure and turbulent quantities. Complex events need to be analyzed with a comprehensive approach without neglecting too many variables to comply with scientific reasoning by avoiding using only theories that assume many simplifications.