@ARTICLE{Tang_Ying_Thermal_Early,
 author={Tang, Ying and Xiao, Li and Yang, Fan and Wu, Xiaodan and Su, Zhan and Zhang, Yue and Jiang, Shixin and Yang, Peng},
 pages={e153839},
 journal={Bulletin of the Polish Academy of Sciences Technical Sciences},
 howpublished={online},
 year={Early Access},
 abstract={The performance of a large-size helical baffle heater in an in-situ operating is investigated using a numerical simulation method. It revealed that the fluid in the shell retains a spiral flow, and the output flow velocity is higher than in the surrounding area. However, the pitch design is rather big, resulting in a low-velocity flow zone on the backwind side. At 100 kW and 500 m³/h, the fluid flow is turbulent. 50 kW and 200 m³/h, the fluid remained laminar. As flow rate rose, the pressure of tar-rich coal formation grew dramatically. The wall temperature exhibited spiral plunger at the inlet, but the bottom temperature was symmetrically distributed. Under low power and flow, Reynolds number change has a greater impact on the combination of Nusselt and Prandtl number. The wellbore experiences higher thermal loads during downhole heating, increasing the possibility of thermal damage dramatically. An increase in the heater shell length improves the total heat transfer performance. Conventional heaters often only heat the bottom formation. Therefore, while optimizing the construction, it is vital to ensure that the weight of heater itself does not exceed the tensile strength of cable, and consider shifting down the perforation outlet or lowering the outlet.},
 title={Thermal Transfer Performance of Downhole Electric Heaters for In-Situ Pyrolysis in Tar-Rich Coal},
 type={Article},
 URL={http://czasopisma.pan.pl/Content/134173/PDF-MASTER/BPASTS-04937-EA.pdf},
 doi={10.24425/bpasts.2025.153839},
 keywords={tar-rich coal, in-situ heat injection, downhole heater, thermal performance, well-wall stability},
}