The cumulative energy effect for improved ignition timing

Abstract

A technique capable of improving timing in ignition applications is proposed. It is based on the use of shock waves propagating in a specific medium that allows achieving extremely high speeds and energies. The model uses the energy cumulation effect in the presence of the shock wave refraction on an interface with plasma. The problem was solved analytically and the effects were demonstrated for a cylindrically symmetrical geometry. Numerical results show very quick and uneven acceleration of different portions of the shock front. Its strong distortions lead to formation of a sharply focused jet near the axis of symmetry. The ability of the shock to achieve extremely high speeds and energies can be useful in design of efficient combustors for hypersonic systems, and possibly offers an alternative way of construction of a nuclear fusion reactor. Recommendations are given in terms of adjustment parameters and can be applied at any problem scale and for various combinations of the strengths of the effects involved in the problem. V C 2015 AIP Publishing LLC. [http://dx.

A mechanism of vortex generation in a supersonic flow behind a gas-plasma interface

“…Here, (x i ,y i ) and (X i , Y i ) are coordinates of the incident and refracted shock front surface at a point of interaction i, and α is the incidence angle at this point ( Fig.1). It will be further assumed in the calculations that the interface is "smooth", the case when the refraction effects become more pronounced [37]. The media on both sides of the interface are considered as ideal gases with initially equal pressures across the interface.…”

“…1). It will be further assumed in the calculations that the interface is "smooth", the case when the refraction effects become more pronounced [37]. The media on both sides of the interface are considered as ideal gases with initially equal pressures across the interface.…”

A Shock Wave Instability Induced on a Periodically Disturbed Interface With Plasma

“…The results of numerical simulation for the shock perturbation evolution (X i , Y i ) based on the system (8) are presented in the Fig.4, for the times between n = 0.3 to 3.1 through the [20], the type of the interface is smooth, and the rest is the same as in the uniform case. The main difference from the uniform case here is that, while the perturbation to the shock steadily grows during the time of crossing and after this, both components of its growth rate, in accordance to (11), are decreasing functions of time for all the interaction points. Graphs in the Fig.…”

Wave Drag Modification in the Presence of Discharges

“…The shock refraction resulting in an increase of the absolute value of the shock velocity along with its vector rotation (at refraction angle γ) occurs at the moment when the shock front crosses the plasma interface. As the refracted shock continues to propagate in hotter medium, its dynamics is determined by the parameter distribution in the plasma volume [17,19,33,35]. Even though the changes in the shock structure become visible only during this time, they are the still consequences of the interaction at both stages: the conditions on the interface are necessary to trigger the front instability, and the gas volume effects provide the means necessary for its positive dynamics.…”

“…In the gas-dynamical approximation, a strong plane shock wave propagating in such a medium accelerates very quickly accumulating virtually infinite energy. This interesting phenomenon, as applied to the shock refraction problem, was considered in [35] assuming the plasma density as changing in the longitudinal (x-) direction only. Applying it to the present geometry, the refracted shock coordinates can be determined as…”