大长径比的 meaning in English

slender

The main results in this paper are as follows : ( 1 ) study on starting up performance of thermosyphon : according to the study on the states before and after starting up of thermosyphon with the various filling amount , it is considered that the phase change heat transfer inside the copper - water thermosyphon with a large ratio of length and diameter is not only influenced by the boiling degree of superheat , but also controlled by evaporation and companied with the boiling of the thin liquid film
本文的主要研究结果为：（ 1 ）热虹吸管启动性能的研究：通过对从不同充液量、启动前状态、内部汽化核心状态对启动的影响所进行的试验研究，认为大长径比的铜?水热虹吸管管内相变不仅仅为沸腾，而是以蒸发为主，伴有薄液膜的沸腾。