Detonation Flashcards
1What is the difference between Humphrey (Atkinson) cycle and Brayton cycle?
Why Humphrey (Atkinson) cycle has a higher theoretical thermodynamic efficiency than that of a Brayton cycle
(Analyse from P-V or T-S diagram)?
The Brayton cycle
Isobaric (Constant Pressure) Heat addition and heat rejection
Humphrey Cycle
Isochoric (constant Volume) heat addition and Isobaric heat rejection
The isochoric heat addition in the Humphrey cycle allows for more efficient energy transfer
Constant volume means no work needs to be done by the thermodynamic system making it more efficient
2 What is the difference between deflagration wave and detonation wave?
Deflagration waves occur at subsonic speeds (M<1)
Propagate at speeds of 1-100 m/s.
Pressure Decreases Volume Increases
Detonation waves occur at supersonic speeds (M>1) a
Propagate on the order of 2000 m/s.
It involves a Shockwave where
Pressure Increases Volume Decreases
3 What are three kinds of engine concepts using the detonation or pressure-gain combustion? Briefly
introduce their working principles.
Pulse detonation engine(PDE)
Cyclically detonates fuels and atmospheric air mixtures to generate power Utilises intermittent detonations in a tube, producing thrust through high-pressure gas tubes and unsteady combustion
Rotating detonation (wave) engine (RDE)
Combustible gas mixture
operates with continuous detonation waves in a circular path, enhancing efficiency with a constant detonation process.
Oblique Detonation Engine (ODE)
Combustible gas mixture
Uses angled shock waves for detonation initiation, suitable for high speed propulsion with efficient shock management.
4 What are the technology challenges of PDE, ODE and RDE?
Pulse Detonation Engine(PDE)
Need for continuous ignition during each operating cycle managing low frequency combustion
High thermal loads
Oblique Detonation Engine (ODE)
Can only be used for hypersonic flows
Stability of detonation wave can be very sensitive to the inflow direction which can be difficult to contain
Rotating Detonation Engine (RDE)
Very unsteady and hard to control. the propagation wave
Outflow from combustor is non uniform
Extremely high thermal loads
What are the jump conditions in detonation?
Jump conditions refer to the changes in flow variables such as pressure, temperature, and velocity across a shock wave in detonation.
Explain the concept of a Rotating Detonation Engine (RDE).
RDE utilizes continuous detonation waves in a circular chamber, providing continuous thrust with higher efficiency than conventional engines.
Describe the Pulse Detonation Engine (PDE) and its operation cycle.
PDE operates by repeated initiation of detonations within a tube, generating pulses of high-pressure gas for thrust, characterized by unsteady combustion.
What is an Oblique Detonation Engine (ODE) and its potential applications?
ODE uses oblique shock waves to initiate detonation, promising in high-speed air-breathing propulsion with potential for improved performance.
How does detonation propulsion compare to traditional jet engines in terms of efficiency and performance?
Detonation propulsion, through mechanisms like PDE and RDE, can potentially offer higher thermodynamic efficiency and better performance at high speeds.
