板耦合型机械排烟与竖井自然排烟协同排烟动力学演化特征研究

The combined ventilation and smoke extraction method with” jet fan + ventilation shaft” is generally adopted in super-long highway tunnel of China. At present, there are only few studies on the smoke exhaust characteristics of the "ventilation shaft", which in charge of the smoke exhaust function of the combined ventilation and smoke extraction method. Beyond that, the “ventilation shaft” system is often treated as the point extraction system, and mechanisms of the coupling effect between the mechanical extraction method and the natural ventilation with shaft are not well understood. Based on the structure of the ventilation shaft, a synergistic smoke extraction method combining the board-coupled shaft method and the mechanical smoke extraction method (MBCS) will be proposed. Through theoretical and experimental studies, the smoke extraction characteristics and the dimensionless parameters related to the smoke extraction can be investigated. By analyzing the smoke flow inside the shaft, the dimensionless function for characterizing the transition of the jet buoyancy smoke from momentum-controlled to buoyancy-controlled can be explored. With the method of experimental study, the relationship between the temperature and CO concentration in the gas discharged from the MBCS can be obtained. And based on theoretical analysis, the model for predicting temperature difference inside and outside the shaft can be developed; combining the relationship between the temperature and CO concentration, the model for predicting CO concentration in the gas discharged from the MBCS can be developed. And finally, the model for predicting the dimensionless smoke and heat extraction performance from the MBCS can be developed. The present study will provide theoretical and technical supports for smoke control and extraction in super-long and deep-buried highway tunnels.

我国特长隧道普遍采用“射流风机+通风井送排式”组合通风排烟方式，目前针对该组合通风排烟方式中承担火灾排烟功能的“通风井”的排烟特性研究较少，且少数相关研究也仅将“通风井”排烟等同作集中排烟处理，未从深层次理解“通风井”排烟时机械排烟与竖井自然排烟协同排烟机制。本项目在“通风井”结构基础上，提出一种板耦合型机械排烟与竖井自然排烟协同排烟方式（MBCS），拟通过理论与实验相结合的方式对MBCS排烟性能及排烟特征参数的无量纲模型进行研究，探索表征MBCS竖井内部浮力射流控制模式转换的特征函数及临界判据，获得MBCS竖井排出烟气的CO浓度与竖井内部温度的关联特征，发展耦合竖井结构特性、薄板特征及机械排烟特性的竖井内外温差预测模型和竖井排出烟气的CO浓度预测模型，建立无量纲MBCS净排出CO体积流率及排热量预测模型。研究成果有望为发展超长、超深埋隧道优化火灾烟气控排方法提供理论基础和技术支持。

我国特长隧道普遍采用“射流风机+通风井送排式”组合通风排烟方式，目前针对该组合通风排烟方式中承担火灾排烟功能的“通风井”的排烟特性研究较少，且少数相关研究也仅将“通风井”排烟等同作集中排烟处理，未从深层次理解“通风井”排烟时机械排烟与竖井自然排烟协同排烟机制，因此开展板耦合型机械排烟与竖井自然排烟协同排烟动力学演化特征研究具有重要的科学意义。本项目通过理论推导、数值模拟及缩尺度实验研究，探索了板耦合型机械排烟与竖井自然排烟协同排烟方式（MBCS）排烟特性影响规律，获得了浮力射流由浮力控制向动量主导过渡的转换临界条件，揭示了MBCS 排烟动力学机理，建立了MBCS排烟性能及排热性能的无量纲预测模型。具体包括：①探索了机械排烟与自然排烟协同排烟影响机制；②建立了竖井内部浮力射流控制模式转换的特征函数；③发展了近火源区和远火源区顶棚烟气无量纲温度分段预测模型；④建立了适用于水平诱导流作用下的火源上方顶棚烟气最高温度预测模型；⑤发展了无量纲竖井内外温差预测模型；⑥构建了竖井排出烟气CO浓度与烟气温度的关联函数；⑦建立解析竖井排热量及排烟量的无量纲预测模型。此外，衍生开展了如下研究：⑧构建了竖井前后烟气层高度之间的关联函数；⑨建立了狭长空间一维羽流区烟气层厚度解析预测模型；⑩探究了水平对冲诱导流的诱发机制及其量化模型，开展了机械通风井的排-控烟协同优化研究。.项目圆满完成了预定的研究目标和任务，在国内外本领域重要学术期刊发表论文6篇，其中Tunnelling and Underground Space Technology、International Journal of Thermal Sciences等SCI高区或本领域顶级期刊论文6篇；培养已转博研究生1人、在读研究生5名，本科毕业生5人。