关键词: 季节冻土区, 埋地管道, 最不利水温, 降温速率, 仿三维数值方法

Abstract: To bury a pipe is a common technique to keep running water warm in the winter. Integral knowledge of water temperature within a buried pipe can provide theoretical basis for decreasing burial depth and keeping water warmer. Also, it has practical significance for popularizing of central water supply engineering. On the basis of quasi-three dimensional numerical method, the effect of soil moister, ground surface temperature, buried depth, pipe diameter, water flow velocity and inlet water temperature when the pipe temperature at lowest are discussed in this thesis. No matter how the above factors change, the water temperature will go down with the conveying distance. The cooling rate of pipe decreases quickly firstly, then slowly with increasing of soil moister and burial depth and rising of ground temperature. When the pipe is buried below the frost line, effect of seasonally frozen soil layer on pipe can be ignored. With decreasing of pipe diameter and water flow velocity, the cooling rate will increase. Water flow velocity has a reciprocal relationship with the cooling rate. Additionally, the pipe cooling rate increases exponentially with the rising of inlet temperature.

Key words: seasonally frozen ground areas, buried pipe, most unfavorable water temperature, cooling rate, quasi-three dimensional numerical method