内冷与喷雾复合冷却式智能车刀及其切削PBX炸药温度监控研究

Because PBX material is a metastable dangerous explosive, the heat generated during its cutting process will bring high security risks. It usually needs pour a large amount of cutting fluid to cool the tool, chip and workpiece, but the coolant is difficult to enter the tool-chip contact area, which also pollute the environment. Due to internal cooling can quickly remove the heat transferred into the tool in cutting process, and spraying air + coolant can effectively cool tool, workpiece and chip with minimum coolant, a smart turning tool system cooled by a combined cooling technique based on internal cooling and spraying air + coolant is proposed so as to meet the requirement of green and safe cutting PBX explosives. The main task is to realize the temperature reduction, measurement and control during the cutting process and also minimize the hazards of cutting fluid. The geometric parameters of the smart turning tool will be optimized by thermal-mechanical coupled simulation analysis considering the interaction between structure and multiphase-fluid. Based on the simulation analysis of heat transfer of the turning tool, the influence of various factors of the combined cooling technique on the cutting temperature will be studied, a mathematical model will be established to predict the cutting temperature in real time. A controller will be developed and integrated into the cutting experiment platform of the smart turning tool, which can stabilize the cutting temperature thus ensure security by optimizing the flow rate of the combined cooling, cutting parameters in the cutting process. This research has great significance for the study of combined cooling technology and its application for green cutting, as well as provides ideas for green and safe cutting of other explosive and flammable materials.

PBX炸药材料是一种亚稳态危险爆炸品，切削过程产生的热量会带来很大的安全风险，通常需浇注大量切削液进行冷却，但冷却液难于进入刀具-切屑的紧密接触区，且污染环境。因内冷却能将传入刀具的热量快速带走，喷雾冷却可以少量的冷却液冷却刀具、工件和切屑，针对PBX炸药的绿色、安全切削需求，本项目提出内冷与喷雾复合冷却式智能车刀系统，以实现切削过程中的温度降低、测量和控制，并减少炸药切削废液的产生。通过建立车刀切削过程中结构与多相流的热-力耦合仿真模型，优化智能车刀结构；通过热分析深入研究内冷与喷雾复合冷却各因素、切削参数等对切削温度的影响规律，建立切削温度预测模型；搭建智能车刀切削炸药实验平台，通过温度控制研究实现切削过程中优化复合冷却参数、切削参数，以使切削温度稳定保证安全。本项目的开展对绿色切削复合冷却技术的研究及其应用具有重要意义，也为其它易燃易爆材料的绿色安全切削提供思路。

PBX炸药材料主要用于武器系统的爆炸和毁伤战斗部中，它是一种亚稳态危险爆炸品，而切削加工是获得一定形状炸药部件的主要方法。本项目面向PBX炸药等危险和难加工材料的绿色安全、高效可靠切削加工的需求，开展了内冷与喷雾复合冷却式智能车刀、切削温度测量及其控制技术的研究。本项目研制出了一种内冷与喷雾复合冷却式车刀，可实现单独循环内冷、单独喷雾和内冷+喷雾等多种冷却条件下的切削；基于Fluent软件，建立了内冷与喷雾复合冷却条件下车刀切削时的流-固耦合传热仿真分析模型，并通过田口方法设计的仿真实验对刀具的喷雾流道结构进行了优化。通过有限元仿真和切削实验研究了喷雾压力、喷雾流量和循环内冷流速等冷却参数对切削温度的影响规律，得出当切削参数一定时随着喷雾压力和内冷流速的增加切削温度逐渐降低，而随着喷雾流量的增加切削温度并不一直降低。通过传热理论分析和有限元仿真，建立了循环内冷进出口冷却液温度与切削温度之间的数学模型以对切削温度进行预测，建立了切削温度的控制策略并进行了模拟，通过TC4钛合金的切削实验验证了所建切削温度预测模型的正确性和切削温度控制策略的可靠性。通过PBX炸药和TC4钛合金的切削实验结果表明，相比干切削内冷与喷雾复合冷却下的切削温度大幅降低，与传统水冷切削相比其切削温度更低，刀具寿命延长、表面加工质量得到提高。本项目设计出了绿色环保、冷却效率高且易集成于机床的内冷与喷雾复合冷却式智能车刀系统，实现了预定的研究目标，为易燃材料镁合金、难加工材料镍合金等的绿色安全高效切削提供理论基础和借鉴，对刀具冷却结构的创新设计和方法也具有重要参考价值。