基于二分法的多竖井送排式通风方式数值解析

多竖井送排式通风方式能将特长公路隧道划分成若干通风区段,通过竖井排出隧道内污染空气并同时送入新鲜空气,因此可以加大纵向通风方式的适用长度.多竖井送排式通风方式的流量守恒和压力平衡方程更加复杂,很难求得其解析解.以流体力学连续性原理和伯努利定理为基础,建立了多竖井送排式通风方式的流量平衡方程和压力平衡方程.基于二分法数值分析方法提出了流量平衡方程数值解的求解过程,并对迭代计算过程中目标函数的确定、初始试算值的界定、计算约束条件的选取作了介绍.以二分法为核心算法,并采用面向对象的编程语言VBA (Visual Basic for Application,以下简称VBA)编制了"多竖井送排式与射流风机组合通风方式"计算程序,该程序已经在多个特长公路隧道通风设计中得到应用,并取得了良好的效果.

Numerical Solution for Multi-Shaft Blow and Exhaust Ventilation Model Based on Dichotomy Algorithm

Multi-shaft ventilation system divides an extra-long tunnel into several sections whose polluted air is exhausted and fresh air is provided through two neighboring shafts.As a result,a greater adaptive length for a longitudinal ventilation system can be achieved.Flow conservation equation and pressure balance equation in a multi-shaft ventilation system are so complicated that it's hard to find the analytic solution.Based on the continuity law and Bernoulli's law in fluid mechanics,the flow conservation equation and the pressure balance equation of the multi-shaft ventilation model are put forward in this article.The dichotomy algorithm is adopted to extract the numerical solution.Besides,the object function,the initial trial value,and constraint conditions of the algorithm are discussed in the article.A software,called Multi-shaft and Jet Fan Integral Ventilation Analysis System,has been developed by using Visual Basic for Application(VBA),a robust object-oriented programming language.The above given software has been applied in several extra-long highway tunnels with satisfactory effect.