The calculation of temperature drop was one of the most important parameters in the repair process of hot oil pipeline, and the value played an important role in the pipeline excavation repair plan and oil transportation. The thermodynamic model of unsteady state after excavation was established from the view of thermodynamics, and the simulation was carried out on the basis of a case study of the hot oil pipeline from Songshan to Jinzhou. The influence of the different starting points, excavation length and oil station temperature on the oil temperature of hot oil pipeline was studied combined with CFD in different seasons of excavation operation of hot oil pipeline and the soil temperature field around the changes of numerical simulation analysis. The results of the study could ensure the safe operation of the pipeline under the premise of providing hot oil pipeline excavation repair recommendations and guide the management department to optimize the construction repair plan.

Carbon brush and slip ring were important parts of the generator excitation system. Due to some factors, the phenomenon of carbon brush getting high temperature or wearing affected the safe generator operation seriously. The force of pressure spring was got on carbon brush by experiment, pressure values of both 8 positive carbon brush and 8 negative carbon brush in two generators were analyzed, the pressure spring pressure of two generators carbon brush was compared, reasons of brush getting high temperature were got , and proposals for change were given.