炉内喷嘴射流刚性的理论模型及试验研究

为增进对炉内燃烧器射流特性和射流与炉内旋转气流相互作用规律的认识，提出了射流出口初期的刚性假设和射流弯曲应力的概念，并以此建立了射流偏斜的弯曲应力分布模型。同时直接从N-S方程出发，建立了射流偏斜的微元体运动模型。在炉内射流的外界条件相同的情况下，分别对矩形喷组射流，水平浓淡风喷嘴射流和刚性问题进行了理论模型分析和试验研究，得到了影响射流刚性的两个关键因素，即：射流的截面形状和射流的动量，首先，燃烧器喷嘴出口截面的几何形状，它决定射流初期的断面形状，射流截面惯性矩JZ和射流抗弯截面模量WZ的大小，从而决定了射流截面各类弯曲应力的大小和分布，它对影响射流刚性的外因-弯曲应力产生了重要影响，是直播影响射流出口初期偏斜的重要因素。其次，燃烧器喷嘴射流出口动量，是决定射流刚性大小的内在因素，即：射流动量越大，则射流刚性越强，偏斜越小。

THEORETICAL MODEL AND EXPERIMENTAL STUDY OF BURNER NOZZLE JET RIGIDITY IN FURNACE

In this paper, to promote the understanding of the burner's jet property and the rules of mutual action between jet and rotating airflows, the concept of jet deflection stress is put forward on the basis of rigid body hypothesis during the initial period at jet outlet and the jet deflection model of stress distribution accordingly. At the same time, the fluid cell kinetic model of jet deflection is established directly from N S equation. Under the same external condition of jet, the theoretical analysis and experimental study for rigidity of rectangle nozzle jet and HBC SSA (horizontal bias combustion pulverized coal burners with side secondary air) nozzle jet are carried on separately. Two key elements, which greatly influenced the jet deflection, i.e. jet cross shape and jet momentum have been acquired. The former determines the cross shape of initial jet, section inertial moment J Z and section modules of resist deflection W Z , thus, all kinds of deflection stress in size and its distribution are confirmed. It greatly affects deflection stress, which is the external element of jet rigidity and also the important factor which directly influence the deflection of initial jet at outlet. The latter is the internal element which influenced the jet rigidity. i.e. The larger the jet momentum, the stronger the jet rigidity and the smaller jet deflection.