Abstract: Based on the actual situation of the pipeline of the liquid nitrogen fire prevention project, the influence of environmental temperature, liquid nitrogen temperature, inlet flow rate, pipe length, pipe diameter, and outlet diameter on the liquid nitrogen content and transportation pressure drop at the pipeline outlet are analyzed. The calculation method for predicting pipeline transportation pressure drop using a homogeneous model was analyzed through simulation and experimental. The results show that the environmental temperature and liquid nitrogen temperature have little influence on the liquid nitrogen content and pipeline pressure drop; The faster the flow rate , the longer the conveying distance, and the smaller the pipe diameter, the more significant the increase in pressure drop; The pressure drop will rapidly increase as the outlet diameter of the pipeline decreases. For low dryness gas-liquid two-phase nitrogen, it is suitable for homogeneous model calculation. The proposed simplified modified empirical model has a good agreement between the predicted pressure drop and experimental values, and can predict the pressure drop of gas-liquid two-phase nitrogen pipeline transportation, thus guiding the engineering application design of liquid nitrogen transportation pipelines.

Key words: energy storage safety, liquid nitrogen pipeline transportation, liquid nitrogen content, pressure drop, homogeneous model, prediction model