1. Dynamics of coking process
during pyrolysis of supercritical hydrocarbon fuel RP-3
Liu, Zhaohui; Pan, Hui; Feng, Song; Bi, Qincheng
State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University，Xi’an , China
Tel: ,
P-225
Abstract：China aviation kerosene RP-3 was used as an endothermic fuel to pyrolyze in an electrically heated horizontal channel with an internal diameter of 4.0 mm at temperatures up to 640 C, pressure of 3.0 MPa. Results indicated that coking process was an unsteady and dynamic one with randomness.
1 Introduction
1.1 Background
Endothermic fuel used as propellant and coolant in scramjets.
Fuel pyrolyzed at temperature up to 750 C.
Wall temperature up to 1000 C.
Cooling structures and passages in scramjet
1.2 Coking process
Coking process was considered to the net result of two simultaneous sub-processes: a deposition process and a removal process.
4 Results and discussion
4.1 Dynamics of pressure drop during coking process
The coking process was unsteady and dynamic.
The coke removal and buildup in a short time made the coke process unsteady.
4.2 Dynamics of heat transfer during coking process
Three stages for wall temperature change:
The wall temperature decreased and tended to achieve steady state in 0-10 min;
The wall temperature hardly changed, but the pressure drop continued to increase at the time of min;
All the temperatures tended to return to the original values, accordant to the dynamics of pressure drop at 26-min.
Wall temperature variations during coking run of Case No. 2
4.3 Oscillation caused by coke deposition
Fuel temperature and pressure drop oscillations during coking run
5 Conclusions
Coking process was the net result of two simultaneous sub- processes: a deposition process and a removal process.
The coking process in a small scale period was an unsteady, dynamic, and random one.
Pressure drop constantly increased during coking run.
Wall temperature achieved steady state in the first minutes.
2 Experimental setup
Kerosene fuel RP-3 pyrolyzed in an electrically heated horizontal channel with an internal diameter of 4.0 mm.
As deposition accumulated, fuel temperature oscillation decreased, but pressure drop oscillation increased.
The oscillation magnitudes for temperature were always opposite to those for pressure drop.
3 Validation for coking measurement
Operating conditions
Validation
Function between pressure drop and coke deposition amount
Fund：National Natural Science Foundation of China (No ), China Postdoctoral Science Foundation (No. 2013M532044)