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Performance Analysis of Normal Shocks in a Flying Machine

Explore the assessment of a flying machine with shocks, focusing on mass, momentum, energy conservation, and the nature of normal shocks in thermodynamics, including irreversibility and entropy. Discover the potential of normal shocks as thermodynamic devices and their impact on supersonic flows.

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Performance Analysis of Normal Shocks in a Flying Machine

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  1. Performance Analysis of Normal shocks P M V Subbarao Professor Mechanical Engineering Department Assessment of A Flying Machine with Shocks!!!

  2. Combined Mass, Momentum and Energy Conservation

  3. Discovery of The Ghost Reversible flow : No entropy generation between x & y,

  4. The Dangerous Ghost Shows existence of an Irreversibility between x & y, The Existence of Normal Shock !!!! This equation relates the downstream Mach number to the upstream Mach Number across a Normal Shock. It can be used to derive pressure ratio, the temperature ratio, and density ratio across a Normal Shock.

  5. Nature of Normal Shock • The flow across the shock is adiabatic and the stagnation temperature is constant across a shock. • The existence of an irreversibile shock will result in a decrease of stagnation pressure. • This is feasible iff

  6. Change in entropy for a perfect gas Obtain ratios of thermodynamic parameters across NS. &

  7. An Ultimate Measure for Possibility of a Fantasy Shock is possible only in supersonic flows Infeasible M

  8. The Nature of Irreversible Phenomenon g =constant=1.4 My Mx

  9. Mach Number Vs Static Pressure : Normal Shock

  10. Mach Number Vs Density : Normal Shock

  11. Mach Number Vs Static Temperature : Normal Shock

  12. Normal Shock as A Thermodynamic Device • A Normal Shock is a zero cost solution to convert available macroscopic kinetic energy into microscopic kinetic energy. • Lead to increase in pressure, temperature and density. • NS is a zero weight compressor. • A highly irreversible device. • A zero cost but inefficient replacement to ????

  13. Thermodynamic Nature of Normal Shock The flow across the shock is adiabatic and the stagnation temperature is constant across a shock. The effect of increase in entropy across a shock will result in change of supersonic to subsonic flow. The severity of a shock is proportional to upstream Mach Number. Normal Shock is A severe irreversible Diffuser. No capital investment. Can we use it as a supersonic diffuser at the inlet of an engine? How to measure the degree of irreversibility of a shock?

  14. Measure of Loss due to Shock Before the shock: After the shock: Across the shock:

  15. Ratio of Stagnation Pressures across A NS

  16. Mach Number Vs Total Pressure : Normal Shock

  17. Mach Number Vs Entropy Generation : Normal Shock

  18. Temperature – Entropy Diagram Kinetic Temperature @ y Kinetic Temperature @ y Temperature Entropy (kJ/kg.K)

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