UJJWAL K SAHA
Articles written in Sadhana
Volume 45 All articles Published: 18 November 2020 Article ID 0285
The addition of ethanol to a blend of vegetable oil (VO) and diesel, in general, has been found to improve the compression ignition diesel engine performance. In the present investigation, the influence of ethanol on Mesua ferrea Linn oil–diesel blend has been studied. Mesua ferrea Linn trees, abundant in the northeastern states of India, have the potential to supplement the fossil diesel. The blend studied is composed of 30% Mesua ferrea Linn oil and 70% diesel by volume (VO30). Ethanol is added 5 and 10% by volume to VO30 binary blend to form two ternary blend VO30E05 (5% ethanol and 95% VO30) and VO30E10 (10% ethanol and 90% VO30). Experiments have been carried out in a four-stroke, single cylinder, water cooled, stationary diesel engine at various engine loads. The addition of ethanol results in an increase of brake thermal efficiency up to 1.5% as compared to neat VO30. The brake specific fuel consumption of the engine increases on an average by 1.8 and 3% with the use of 5 and 10% ethanol, respectively. The use of ethanol results an increase of CO and HCemissions while a decrease of NOX emission
Volume 46 All articles Published: 11 April 2021 Article ID 0076
The nozzle forms a large segment of the rocket engine structure, and as a whole, the performance of a rocket largely depends upon its aerodynamic design. The principal parameters in this context are the shape of the nozzle contour and the nozzle area expansion ratio. A careful shaping of the nozzle contour can lead to ahigh gain in its performance. As a consequence of intensive research, the design and the shape of rocket nozzles have undergone a series of development over the last several decades. The notable among them are conical, bell, plug, expansion-deflection and dual bell nozzles, besides the recently developed multi nozzle grid. However, to the best of authors’ knowledge, no article has reviewed the entire group of nozzles in a systematic and comprehensive manner. This paper aims to review and bring all such development in one single frame. Thearticle mainly focuses on the aerodynamic aspects of all the rocket nozzles developed till date and summarizes the major findings covering their design, development, utilization, benefits and limitations. At the end, the futurepossibilities of development are also recommended.