Liquid dinitrogen tetroxide (N204)tends to change to solid phase in low tempera—
ture which may affect the launch pmgress.BaSed on the theory 0f tmnsient heat conduction,the
tmnsient heat conduction of N204 in pipes of difkrent diameters was researched,and the transient
heat conduction model of N204 in low temperature was established.Tests show that the experimental
and the model results are in good accordance.