注浆喷嘴仿生设计及增效降耗机理研究

Nozzle is a direct component of forming jet in high pressure jet grouting, which can solve the problem of drag reduction and wear resistance of the nozzle, and effectively improve the working efficiency of the jet grouting. This project from the perspective of bionics, the excellent performance bionic coupling non-smooth structure models with double properties of drag reduction and wear resistant are constructed by the modular idea. Considering the situation of fluid flow inside the nozzle cavity and the structure characteristics of the nozzle, and the ease of nozzle processing, using theoretical analysis, orthogonal experiment, numerical simulation, test block model erosion experiment, SEM test and analysis as the main research method, putting the bionic coupling non-smooth structure models reasonable into the structure design of nozzle to develop the bionic coupling nozzle. Comprehensive the experimental results indoor and outdoor, and statistical regression analysis on the experimental data, constructing the constitutive equation between jet operating efficiency and energy consumption of the bionic coupling nozzle and ordinary nozzle, and combining with the results of numerical simulation, comparative analysis of the differences between these two kinds of nozzles about drag reduction, wear resistance and energy consumption, from two aspects of qualitative research and quantitative research to reveal the mechanism of increasing efficiency and reducing consumption of the bionic coupling nozzle. The research has important theoretical significance and realistic significance that it will enrich the existing nozzle structure design theory, broaden the range of application of bionic non-smooth theory, improve the operation efficiency of high pressure jet grouting, reduce the equipment energy consumption and the comprehensive cost of the operation, and energy conservation and emission reduction, etc.

喷嘴是高喷注浆作业时形成射流的直接元件，解决喷嘴的减阻和耐磨问题，将有效提升高喷注浆的作业效率。本项目从仿生学角度出发，以模块化思想构建性能优良且兼具减阻、耐磨双重特性的仿生耦合非光滑结构模型；综合考虑流体在喷嘴内腔流动时的流场情况、喷嘴结构特点和加工难易程度，以理论分析、正交试验、数值模拟、模型试块冲蚀实验、SEM测试分析为主要研究手段，将仿生耦合非光滑结构模型合理融入喷嘴的结构设计中制得仿生耦合喷嘴；综合室内和室外实验测试的结果，对其进行统计回归分析，并分别构建仿生耦合喷嘴和普通喷嘴的射流作业效率与能耗之间的本构方程，结合数值模拟的结果，对比分析两种喷嘴的减阻、耐磨和能耗差异，从定性和定量方面揭示仿生耦合喷嘴的增效降耗机理。本项研究对丰富现有喷嘴结构设计理论、拓宽仿生非光滑理论适用范围、提升高喷注浆作业效率、降低设备能耗和作业综合成本，以及节能减排等，都具有重要的理论意义和现实意义。

对高喷注浆的关键执行元件喷嘴进行结构优化设计，对于提升高喷注浆作业效率、降低作业综合成本是极其重要的。以自然界中体表具有非光滑结构的典型生物为仿生原型，以沟槽、棱纹、凹坑和凸包结构为仿生单元，构建具有不同表面的模型试件，并开展了相应的流体减阻和抗冲蚀磨损特性对比研究；将仿生非光滑理论融入常规喷嘴的结构设计中，分别构建了注浆用常规喷嘴和仿生非光滑喷嘴的结构模型，并对两种喷嘴进行了结构优化研究，揭示了仿生非光滑喷嘴具有增效降耗效应的机理。研究结果表明：①同种模型试件的流体减阻效果随着其规格的增大而提升；非光滑结构有效改变了试件底面液流的流动状态，在内凹的沟槽区域中均存在着低速区，处于该区域中的流线具有涡流状的特性；随着液流流速增大，试件底面所受的摩擦力也增大；②沟槽型和凹坑型表面试件的抗冲蚀磨损性能优于光滑表面、棱纹型和凸包型表面试件；③仿生非光滑喷嘴的高喷注浆射流冲击力随着其出口直径的增大而显著增大，随着其长径比的增大而先增大后减小，随着其收缩角的增大而增大，随着矩形沟槽宽度和深度的增大而增大，随着矩形沟槽个数的增多先减小后增大；④均匀布设于喷嘴入口接入段、收缩段和出口段的内部流道壁面上的矩形沟槽结构均具有增效降耗的效果，其最大减阻率可达1.5392%；矩形沟槽型仿生非光滑喷嘴的抗冲蚀磨损性能优于其它类型的喷嘴，可在一定程度上延长喷嘴的使用寿命；⑤涡垫效应、推进效应、流体轴承效应和抗冲蚀磨蚀效应是仿生非光滑喷嘴注浆高喷注浆得以增效降耗的主因，而设置于喷嘴内部流道壁面上的若干矩形沟槽结构与处于其内的反转涡流是关键。本研究为高效喷嘴的结构设计提供了新思路，具有一定的理论意义和实用价值。

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