自然通风地道最佳长度的确定

Deciding the Optimum Length of Tunnel with Natural Ventilation

从获得最大自然通风的角度，分析地道最佳长度存在的必然性．通过建立空气出口温度、热压大小、流动阻力损失等随地道长度变化的关系，提出简单而有效的确定方法．同时考察各种因素如进出口高差、地道等效直径、局部阻力系数、室外空气相对于年平均温度的剩余温度等，对最佳长度和最大流速的影响．通过算例进一步阐明该方法的实施过程，所得结果有利于地下自然通风系统的设计建造及经济利用．

From the angle of obtaining maximal natural ventilation for a tunnel,the author analyses the necessity of the existence of an optimal length;and advances corresponding method for its determination. Moreover, the author inspects the effects of factors difference in height of inlet and outlet, equivalent diameter of the tunnel, local drag coefficient, and residual temperatutre of outdoor air relative to annual mean temperature on the optimal length.These are of practical significance for the design,the construction and the economical utilization of an underground system with natural ventilation.