Search Results

Environmental Control System (ECS) of an aircraft is a complex system which operates classically in an air standard refrigeration cycle. ECS controls the temperature, pressure and flow of supply air to the cockpit, cabin or occupied compartments. The air cycle system of ECS takes engine bleed air as input. Parameters like bleed air pressure and temperature, mass flow, the external factors like ambient temperature, pressure, and aircraft attitude affect the performance of ECS to a large extent especially during transient. So, it is very important to consider the transient characteristics of these parameters in the design stage itself in order to ascertain the dynamic response of the system. This paper explains in detail the importance of transient input characteristics during the detailed design of ECS. A typical temperature control scheme for combat aircraft ECS has been studied and modeled in LMS AMESim.

Compression Ignition engines are widely used for irrigation purpose in rural areas, which generate more noise and vibrations. In this research, neat diesel and Pongamia biodiesel blend (B20) were fuelled in a compression ignition engine to study its noise, vibration and combustion characteristics at the fuel injection pressure of 200 and 250 bar and the fuel injection timings of 21, 23 and 25 degree bTDC at a constant engine speed of 1500 rpm under various loading conditions from no load to full load. From the experimental results, a strong correlation was observed between the heat release rate and the engine noise as the heat release rate was directly proportional to the magnitude of the engine noise. The noise level found increased with increasing load while running on diesel and decreased while running on biodiesel. The maximum noise level of 80.3dB and 78.3dB was observed at 60% load condition for the diesel and biodiesel blend respectively.

Biodiesel production from the waste oils and fats are the cost effective methods and prevents the environmental pollution by proper disposal techniques. Converting waste oils/fat into biodiesel using alkaline catalyst is difficult, as it contains more than one percent Free Fatty Acid (FFA) which will form soap during the transesterification process. Hence, it is desirable to reduce the level of FFA lower than one percent for biodiesel production using the pre-treatment process. In the present research work, ferric sulfate (solid catalyst) is used as a catalyst, because it converts FFA efficiently than the homogeneous acid catalyst which is corrosive in nature and takes longer reaction time.