NUMERICAL SIMULATION OF A THERMAL PLASMA FLOW CONFINED BY MAGNETIC MIRROR IN A CYLINDRICAL REACTOR Authors: Gabriel Torrente Julio Puerta Norberto Labrador Universidad Simón Bolívar Departamento de Ciencias de lo Materiales Departamento de Física Centro de Ingeniería de Superficies

ANTECEDENTS: First Plasma reactor designed and constructed with a grant by FONACIT project of AlN synthesis in a thermal plasma reactor Thermal Plasma Reactor with Expansion Chamber

RESULTS OF ANTECEDENTS: 8.a 8.b Problem: Few Thermal Carbonitridation level of Al 2 O 3

Solution for the enhancement of nitridation: 1. Increasing the power of the thermal plasma. 2. Increasing the resident time of the powders in the high thermal zones of reactor. 3. Decreasing the thermal energy loss of reactor. the energy cost of the process increase the energy cost of the process does not Increase Then, it is convenient to: 1.Design the thermal plasma reactor in fluidized bed for increase the resident time. 2. Confine the thermal plasma flow by magnetic mirror for decrease the energy loss.

New design Plasma Torch Magnetic Coils Graphite tube Refractory Tube Wall Reactor

First step NUMERICAL SIMULATION OF A THERMAL PLASMA FLOW CONFINED BY MAGNETIC MIRROR IN A CYLINDRICAL REACTOR Control Volume The numerical simulation of this thermal axisymmetry plasma jet in magnetic mirror is carried out using two-temperature model to study how changes the electron density and the plasma flux whit the temperature, pressure and with the applied magnetic fields.

Governing Equation Initial Conditions Where the cross section impact and average initial temperatura are:

Boundary conditions In the Central Axel In the reactor wall

State Equation Continuity Equation Momentum Conservation Equations (Navier-Stoke Equations)

Energy Conservation Equations Where Energy transport from the electron to plasma gas Collision frequency

Saha Ionization Equation Ohm Generalized Law

Hypothesis and Data Maxwell Equations Biot-Savart Law 1. Pressure, Heat Capacity Gas (Cp g ), Viscosity Gas (  ) and Thermal Conductivity Gas (K) are constants. 3. The dissociation energy is neglected. 4. Axial Symmetry 5. Only magnetic field in axial direction 6. Power Plasma Torch = 10,5 KW; mass flow= 13,2 lpm of Nitrogen, Bz max = 0,3 T, Ionization Energy = 15,4 eV

Results Axial velocity Profile Pressure = 1 atmosphere ( Pa) Pressure = 1 Torr (133 Pa)

Plasma Temperature Profile Pressure = 1 atmosphere ( Pa) Pressure = 1 Torr (133 Pa)

Electronic Temperature Profile Pressure = 1 atmosphere ( Pa) Pressure = 1 Torr (133 Pa)

Density Plasma Profile Pressure = 1 atmosphere ( Pa) Pressure = 1 Torr (133 Pa)

Electronic Density Profile Pressure = 1 atmosphere ( Pa) Pressure = 1 Torr (133 Pa)

Z ionization Profile Pressure = 1 atmosphere ( Pa) Pressure = 1 Torr (133 Pa)

50 mm Plasma Torch

Conclusions The axial velocity has few changed with the pressure. The Plasma Temperature has few changed with the pressure. The electronic temperature has few increasing with the vacuum The Plasma and Electronic densities decreases with the vacuum. Z ionization increases with the vacuum.