Hydrodynamic thermal explosion

The behavior of liquid flow in micro-tubes and channels depends not only on the absolute value of the viscosity but also on its dependence on temperature. The nonlinear character of this dependence is a source of an important phenomenon - hydrodynamic thermal explosion, which is a sharp change of flow parameters at small temperature disturbances due to viscous dissipation. This is accompanied by radical changes of flow characteristics. Bastanjian et al. (1965) showed that under certain conditions the steady-state flow cannot exist, and an oscillatory regime begins. 

A steady-state solution of Eq. (3.30) exists only for < 2. At z > 2 hydrodynamic thermal explosion occurs and oscillatory flow takes place. 

Bastaniian SA, Merzhanov AG, Xudiaev SI (1965) On hydrodynamic thermal explosion. Sov Phys Docl 163 133-136... 

Now let us show that in the nonisothermal motion of fluid in tubes and channels some critical phenomena may occur related to the existence of a maximum admissible pressure gradient. Once this value is exceeded, the steady-state flow pattern is violated. This is accompanied by an accelerated decrease in the apparent viscosity and increase in the fluid velocity. This phenomenon is known as the hydrodynamic thermal explosion [52] and is caused by the nonlinear dependence of the apparent viscosity on temperature. Specifically, under certain... 

Since the critical conditions of hydrodynamic thermal explosion are characterized by the limit values en - 2 and b = 1, it follows from (6.6.14) that... 

The idea of a dynamic fragmentation model, which calculates the characteristic melt diameter as a function of instantaneous hydrodynamic conditions, was first proposed by Camp in Ref, 30. A model using this idea was later incorporated into a version of the Thermal Explosion Analysis System (TEXAS)one-dimensional FCI code by Chu and Corradini, using an empirical correlation derived from data obtained in the FITS experiments. The fragmentation model in IFCI is a version of a dynamic fragmentation model developed by Pilch based on Rayleigh-Taylor instability theory and the existing body of gas-liquid and liquid-liquid drop breakup data. 

J. Zinn R.N. Rogers, JPhysChem 66, 2646-53(1962) CA 58, 3262(1963) (Thermal initiation of expls) 40b) C.L. Mader, "The Hydrodynamic Hot Spot and Shock Initiation of Homogeneous Explosives ,... 

When the jet is released into the ambient medium, a combination of hydrodynamic instabilities and thermal non-equilibrium conditions in the flow expands the jet. Violent and explosive characteristics of the jet cause its break-up into smaller droplets. This process is referred to as flash atomization. 

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