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Negative Additive Manufacturing of Complex Shaped Boron Carbides
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Zero-Dimensional Ignition Model of Boron Agglomerates.

Lian Duan1, Zhixun Xia1, Binbin Chen1

  • 1National University of Defense Technology, Changsha 410073, P. R. China.

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Summary
This summary is machine-generated.

This study develops a new numerical model for predicting boron agglomerate ignition time in ramjet engines. The model accurately accounts for diffusion resistance and oxide layer effects, improving predictions over single-particle assumptions.

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Area of Science:

  • Combustion Science
  • Chemical Engineering
  • Materials Science

Background:

  • Boron agglomerates are prevalent in ramjet combustion chambers.
  • Existing ignition time models for boron agglomerates rely on single-particle assumptions, leading to inaccuracies.

Purpose of the Study:

  • To develop an accurate numerical model for predicting the ignition time of boron agglomerates.
  • To improve the understanding of boron agglomerate ignition mechanisms in ramjet combustors.

Main Methods:

  • The model is based on Kuo's single-particle boron ignition model.
  • Incorporates Thiele modulus and effectiveness factor to represent diffusion resistance within agglomerates.
  • Corrects evaporation and heterogeneous reaction rates considering oxide layer diffusion and consumption.

Main Results:

  • The developed model shows reasonable consistency with experimental data for ignition time.
  • Investigated the impact of parameters like pore diameter, oxide layer thickness, particle size, O2/H2O concentration, and pressure on ignition time.

Conclusions:

  • The established boron ignition model is a valuable tool for studying agglomerate ignition mechanisms.
  • The model can be integrated with flow analysis for detailed simulations of turbulent combustion in ramjet engines.