ACD505 Session 10

Thrust is the force which moves any aircraft through the air. Propulsion system is the machine that produces thrust to push the aircraft forward through air. Different propulsion systems develop thrust in different ways, but all thrust is generated through some application of Newton's third law of motion. A gas (working fluid) is accelerated by the engine, and the reaction to this acceleration produces the thrust force. Further, the type of power plant to be used in the aircraft depends on four important factors, namely: the aircraft mission, over all weight, flying range and endurance and altitude of flight. This assignment work was partitioned into three different parts (A, B and C respectively). In Part-A, a debate was made on the viability of implementation of twin engine propulsion system for long range civil aircrafts. Logical arguments based on literatures collected from various internet and text book sources were made and the conclusion of the usage of twin engine propulsion system for long range civil aircrafts was drawn. In Part-B, for the given mission of the aircraft, suitable power plant was chosen (Turbo fan engine) and corresponding cycle analysis calculations was done. The calculations were repeated for a range of flying altitudes and performance plots drawn were critically examined. Also, for the given Turbo prop engine data, cycle analysis calculations were done. The calculations were repeated for a set of Mach numbers and performance plots drawn were critically examined. The different engine installation techniques for a turboprop engine was also discussed. In Part-C, flow over an axial gas turbine cascade was analysed in Ansys-FLUENT software package. The blade geometry was created in Ansys-BladeGen and then imported to CATIA to create the flow domain. Meshing of the geometry was done in Fluent-ICEMCFD. The total momentum thrust and propulsion efficiency for the selected turbofan engine for the extreme altitudes of 4km & 18km was estimated as 73541N & 9375N and 47% & 40% respectively. The percentage of cold thrust generated at 4km & 18km was 60% & 45% respectively. Both momentum thrust and propulsion efficiency of the engine was observed to decrease with increase in altitude. The propeller thrust and power for the given turboprop engine for flight Mach corresponding to 0.1 & 0.8 was estimated to be 191669N & 25546N and 6074467W & 6477144W respectively. With increasing Mach number of flight, propeller thrust and power was observed to decrease and increase respectively. For the flow analysis over the axial turbine cascade, maximum static pressure value occurs for +150 (2.67*105 Pa) and minimum for 00 (2.5*105 Pa) flow incidence angles respectively. The maximum Mach number value occurs for +150 (1.89) and minimum for -150 (1.57) flow incidence angles respectively. Further the pressure loss was observed to be minimum for -150 (0.1118) flow incidence angle and maximum for +150 (0.2538) flow incidence angle.