Burning of solid crystalline hydroxylammonium nitrate (HAN) and its water s
olutions is studied in a constant-pressure bomb within the pressure range f
rom 0.1 to 36 MPa, Abnormally high pressure exponents are found to be typic
al of combustion of the crystalline substance, its approximate to 9-mole/li
ter water solution, and a solution containing ethanolamine nitrate as a fue
l: for pressures below approximate to 10 MPa, the burning rate is proportio
nal to the 1.5-2.6 power of pressure. Crystalline HAN retains this tendency
up to approximate to 20 MPa, whereas the solutions burning in the turbulen
t regime show a sharp decrease in the pressure exponent if the pressure exc
eeds 10 MPa, In some instances, as was found in previous works, the burning
rate even decreases with increasing pressure. Special features of turbulen
t burning are explained. A model is proposed to describe the steady-state b
urning of solid HAN, Kinetic parameters of the leading reaction are derived
.