Analisis kegagalan detonasi akibat proses difraksi

Theoretically, detonation wave propagated in combustible gas mixture can be suppressed by chemical and physical method. Although both methods are possible to be implemented in industrial fields, the physical method is more interesting due to its simplicity and flexibility. In physical method, the detonation wave is transformed to be deflagration wave by mechanism of diffraction by an expansion wave. However, the diffraction mechanism itself is very difficult to be analyzed due to 3-dimensional effects of detonation flow field. In this experiment, the 3-dimensional effects are reduced by using single gap orifice diffracting detonation to 2 directions. Single gap orifice made from aluminum material was installed into detonation tube filled by stoichiometric condition of hydrogen-oxygen mixture with an initial pressure of 50 kPa. The detonation wave diffracted from the model in over driven mode is quickly decayed to condition which lower than Chapman-Jouguet condition. The decreasing of the detonation wave velocity along diffraction process is caused by an expansion wave around corner of the model and it reduces pressure and temperature behind the shock wave. The decreasing of pressure and temperature behind the shock wave will reduce rate of the chemical reaction and detach it from the shock wave. Keywords: deflagation, detonation, shock wave, diffractio

FLAMMABILITY LIMITS CAMPURAN LPG-UDARA DAN LPG-OKSIGEN DENGAN DILUENT ARGON

Although Government policy in terms of household fuel conversion from kerosene to fuel Liquefied Petroleum Gas (LPG) provides great savings on huge state subsidies in the energy sector. But, this conversion process also gives a great impact in terms of safety of users of LPG, which in general are people who do not get a good education about safety and procedures regarding the use of LPG gas, so often reported gas leak accident that resulted in fires. Therefore, understanding the characteristics of LPG gas mixed with air become very important to note, in this case is the flammability limit of mixture. By understanding the flammability limit of mixture it will be easier to avoid the accidental fire or explosion. In this experiment, flammability limits are tested with a test detonation of a pipe (PUD) in a circle with a diameter of 50 mm and with a total length of 6000 mm which is divided into two parts, namely 1000 mm for the drivers and 5000 mm for the driven. In the PUD installed four pressure sensors to determine the pressure profile at one point and also posted four ionization probes to record the flame front. Fuel mixture used in the driver is a stoichiometric mixture of hydrogen mixed with oxygen at 100 kPa initial pressure driven while for the mixed-use LPG fuel - air with initial pressure of 100 kPa. Ever greater of addition of argon diluents mixing of fuel of LPG-air and also of LPG-oxygen hence area of flammability limit will smaller, caused by value of ekuivalence ratio will progressively shift and and so do activation of energi of fuel mixture also will be downhill because of release heat reaction of the fuel to argon diluents

Recent Progress on the Implementation of Renewable Biodiesel Fuel for Automotive and Power Plants: Raw Materials Perspective

The issue of energy availability and the impact of global warming has become a specific concern for researchers in various countries in the world. This condition opens up space for potential alternative energy sources that are newer and more sustainable. Biodiesel as a sustainable alternative energy can be applied directly to industrial and automotive fields and even as a fuel source for power plants. This study provides a specific overview of the use and development of biodiesel as a fuel source for renewable power generation based on material sources. An essential part of this study discusses the development of various combinations of biodiesel mixtures and their applications in various types of industries. The physical and chemical characteristics of various types of biodiesel have been studied for their use in various parts of the world. The use of biodiesel has a positive effect on reducing emissions and pollutants, but a particular method is needed to optimize the efficiency and effectiveness, both technically and nontechnically. However, the utilization accompanied by optimizing the characteristics and parameters of biodiesel shows that this alternative energy is feasible and can be applied as a renewable fuel source for automotive industry and power generation in the future