Effects of RP-3 coke deposition on heat transfer under supercritical pressure

The effect of coking deposition of RP-3 on heat transfer was investigated experimentally. The fuel flowing through miniature tube was heated from 127°C to 450°C at 5 MPa, and the mass flow rate was maintained at 3 g/s. The surface coking deposition was obtained by weighting method. Test results show that the effect of coking deposition on heat transfer could be divided into three regions due to differences of deposition: stable heat transfer region at low fuel temperature, deteriorated heat transfer region at peak coking deposition position and short term enhanced heat transfer region at high fuel temperature. Due to lower fuel temperature at the entrance region, the coking deposition amount was tiny and its effect on heat transfer could be ignored. At peak coking region, heat transfer resistance increased sharply with coke deposition, heat transfer coefficiency decreased by 36.1%, and heat transfer deterioration was observed in the whole time. In addition, short term enhanced heat transfer occurred due to the roughness increase by coke particles adhered to the inner surface of the pipe and chemical heat absorption caused by cracking coke deposition. As more and more coke particles adhered, the increasing heat transfer resistance resulted in heat transfer deterioration.