High-Resolution Projectile Velocity And Acceleration Measurement Using Photonic Doppler Velocimetry

This paper describes the new photonic Doppler velocimetry (PDV) technique for measuring time-resolved projectile velocity and acceleration profiles for full flight of the launch package in a two-stage light-gas gun (LGG). This technique is shown to provide excellent temporal and spatial resolution in measurement. Two non-linear acceleration stages were observed for the first time on the LGG. When the gun bore was at atmospheric pressure, a strong opacity was observed during hypervelocity projectile motion >2200 km/s.Mechanical Engineerin

Materials Design - Towards a Functionally Graded Electrical Conductor

In this study, we discuss functionally graded (FG) materials as pulsed electrical conductors. These conductors can be designed to be more efficient and longer lasting by applying numerical modeling tools. One focus is on limiting the thermal fatigue damage in conductors caused by very high temperatures that develop during pulse heating. We have quantified the effect of various grading functions on the pulsed Joule heating generated and the peak temperature experienced in the conductors of an electromagnetic launcher by using a 1D numerical code and a state of the art 3D coupled finite element code, EMAP3D. Because FG materials incorporate applications-tailored compositions, structures, and dimensions, smoothly graded properties in lateral and longitudinal cross sections are obtainable. The Solid Freeform Fabrication (SFF) processing approach allows for architectures with a series of important features. These features include the selective use of high efficiency conducting materials in the core, preconditioned conductor/structure interfaces, and built-in features for enhanced cooling where necessary.Mechanical Engineerin

Study of hybrid energy system based on wind-diesel engine system

The aggravated increase in energy demand has posed a serious problem for the power system’s stability and reliability, and hence has become of major concern. The shortcomings of conventional source of energy have paved way for renewable energy sources. The latter can form a part of a stand-alone system or grid connected system. A single renewable source of energy when integrated with other sources of energy it is termed as hybrid system. This thesis deals with wind-diesel engine system. Wind diesel hybrid systems (WDHS) obtain maximum contribution from wind and rest by diesel generators. They are handy for rural or island areas. In this thesis an active power control strategy has been developed such that when the wind alone is not able to meet the energy demand, without compromising the frequency a transition occurs to wind diesel mode so that the energy demand is met. Then the system’s dynamic performance is compared for two cases with squirrel cage induction generator and permanent magnet induction generator. The mathematical model considered uses a STATCOM to meet the reactive power need upon sudden step change in power. The performance and the analysis is done in a user friendly MATLAB/Simulink environment