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Introduction to Explosions and Explosion Safety

Introduction to Explosions and Explosion Safety. Instructor: Prof. K. Ramamurthi, Department of Mechanical Engineering, IIT Madras. Starting with the definition of the word explosion, the conditions for which disruption of things at the site of the explosion would occur and examples of the different categories of explosions are discussed. The mechanism of formation of shocks and blast waves are investigated and predictions for a blast wave using the Buckingham Pi theorem are given. The equation for a shock Hugoniot is derived from the conservation equations and the jump in pressure, temperature, density across a constant velocity shock wave is calculated. The impulse and overpressure across a blast wave is thereafter modeled and the scaling laws arrived at for determining overpressure and impulses. Explosion length is introduced as an appropriate scaling parameter. Since the energy release rates must be fast enough to drive an explosion, methods of predicting energy release and energy release rates are dealt with. Induction time is defined and a long induction time or equivalently a high value of activation energy is seen to be essential for an explosion to occur. (from nptel.ac.in)

Lecture 18 - Thermal Theory: Characteristic Heat Release and Heat Transfer Time


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Lecture 01 - Loud Bang and Disruption
Lecture 02 - Blast Wave in an Explosion: Predictions from Dimensional Considerations
Lecture 03 - Typical Examples of Explosions and Classification
Lecture 04 - Shock Hugoniot and Rayleigh Line
Lecture 05 - Properties behind a Constant Velocity Shock
Lecture 06 - Blast Waves: Concentration of Mass at the Front, Snow Plow Approximation, Energy Conservation in a Blast Wave
Lecture 07 - Blast Waves: Decay of a Strong Blast Wave, Explosion Length, Sach's Scaling, Overpressure, Cranz-Hopkinson Scaling Law of Overpressure
Lecture 08 - Blast Waves: Overpressure and Impulse in the Near and Far Field, Examples, Introduction to Impulse
Lecture 09 - Blast Waves: Non-dimensional Impulse, Cranz-Hopkinson Scaling, Missiles, Fragments and Shrapnel, Craters, Examples
Lecture 10 - Blast Waves: Interaction with Objects, Reflection and Transmission of Blast Waves, Impedance
Lecture 11 - Blast Waves: Amplification of Reflected Blast Waves; Role of Impedance, Spalling, Damage to Organs Containing Air, Mushroom Cloud in an Explosion
Lecture 12 - Blast Waves: Damage from Blast Waves, Multiple Spikes in an Impulse, Iso-damage Curve on an Overpressure-Impulse Diagram
Lecture 13 - Energy Release in a Chemical Reaction: Moles, Internal Chemical Energy, Standard Heats of Formation
Lecture 14 - Energy Release: Stoichiometry, Equivalence Ratio and Heat Release in Fuel Rich and Oxidizer Rich Compounds
Lecture 15 - Energy Release: Examples of Energy Release Calculations, Higher and Lower Calorific Values, Internal Energy of Formation
Lecture 16 - Rate of Energy Release: Concentration, Activation Energy, Energy Release Profile
Lecture 17 - Thermal Theory of Explosion: Lumped Mass Assumption, Heat Release and Loss
Lecture 18 - Thermal Theory: Characteristic Heat Release and Heat Transfer Time
Lecture 19 - Role of Chain Carriers in an Explosion
Lecture 20 - Combustion: Combustion Waves Involving Flames, Flame Structure, Pressure Drop
Lecture 21 - Combustion: Ignition Kernel, Quenching Distance, Minimum Ignition Energy
Lecture 22 - Case Histories of Explosions Involving Volatile Liquids, Minimum Oxygen Concentration
Lecture 23 - Detonation
Lecture 24 - Detonations: Multi-head Shock Front in a Detonation
Lecture 25 - Detonations: Realizable States in a Hugoniot
Lecture 26 - Detonations: Calculation of Chapman Jouguet Velocities, ZND Structure
Lecture 27 - Case Histories of Explosions Involving Detonation or Quasi-Detonation
Lecture 28 - Explosions in Closed Vessels: Explosions in Confined and Unconfined Geometries
Lecture 29 - Dust Explosions: Sizing of Vents, Dust Explosion, Estimation of Concentration
Lecture 30 - Dust Explosions: Parameters of Dust Explosions, Ignition Energy, Violence
Lecture 31 - Physical Explosions from Flash Vaporization, Metastable Liquid
Lecture 32 - Rupture of Cryogenic Storage Vessels and Pressure Vessels
Lecture 33 - Condensed Phased Explosives based on Hydrocarbons
Lecture 34 - Condensed Phase Explosions: Inorganic Explosive and Characteristics
Lecture 35 - TNT Equivalence and Yield of an Explosion: Non-ideal Explosions
Lecture 36 - Atmospheric Dispersion: Insolation, Temperature Inversion, Atmospheric Stability
Lecture 37 - Atmospheric Dispersion: Dispersion of a Given Mass Release and a Steady State Mass
Lecture 38 - Examples of Explosions Involving Atmospheric Dispersion
Lecture 39 - Quantification of Damages in an Explosion: Dose Response Curves
Lecture 40 - Risk Analysis for an Explosion