This research uses numerical modeling to study the jet cooling properties of hot‐rolled seamless steel tubes under axial movement and circumferential rotation. The orthogonal test is used to examine the effects of axial velocity V , rotation speed R , jet distance S , and jet Reynolds number Re on the surface temperature distribution of steel tubes. The findings demonstrate that the temperature of the steel tube exhibits a “similar sinusoidal function” distribution along the circumference, with various angular frequencies and starting phases as a result of various cooling sites. It is determined that the axial velocity has the greatest influence on the temperature drop during the cooling process of steel tube, followed by the jet Reynolds number, the jet distance, and the rotation speed. When the axial velocity is 0.3–0.7 m s −1 , the rotation speed is 30–45 rpm, the jet distance is 75–100 mm, and the jet Reynolds number is 38 000–51 000, the steel tube cooling efficiency is the best. The mathematical models of temperature drop Δ T and axial velocity V , rotation speed R , jet distance S , and Reynolds number Re are established. The maximum deviation of temperature drop between numerical simulation and mathematical model is only 1.02 °C with high prediction accuracy.

The average jet flow rate, vapor volume fraction inside the nozzle, and the distribution of pressure, shear force, turbulence intensity, temperature, and Nusselt number on the heat transfer surface were simulated when water jet impinged on a 900 C steel plate by a straight cone nozzle and an angular nozzle under the condition of 0.7 MPa inlet pressure. Results indicate that the strong cavitation effect of the angular nozzle makes its jet impingement heat transfer intensity superior to the straight cone nozzle. Although the average jet flow rate of the angular nozzle is 3.33% lower than that of the straight cone nozzle, its shear force, turbulence intensity and Nusselt number at the stagnation point are 18.43%, 20.43%, and 18.81% higher than those of the straight cone nozzle. Experiments also show that the jet impingement heat transfer intensity of the angular nozzle is better than that of the straight cone nozzle. Its maximum cooling rate at the stagnation point increased by 13.16%, and the time to reach the maximum cooling rate decreased by 60%, compared with the straight cone nozzle. It is hoped that the results can help improve the performance of online cooling equipment for hot -rolled steel.

In order to reduce the pressure loss of the nozzle and boost the efficiency of jet impingement heat transfer, this article takes the flow coefficient as the target variable and uses response surface methodology to optimize the straight cone nozzle's internal structure. The optimal structural parameters obtained are as follows: the contraction angle is 30 degrees and the lengths of the contraction section and the outlet section are 5 and 2 times of the outlet diameter, respectively. Besides, the influence of nozzle structural parameters on the heat transfer characteristics of a single water jet impinging on a high-temperature steel plate are simulated by ANSYS-Fluent. According to the results, the optimized nozzle has the largest flow coefficient, and the average Nusselt number on the steel plate is also the largest under the same inlet pressure.

为促进小班化教学质量的稳定性和均衡性,增强学生参与感和获得感,利用监督评价和学生评价信息对材料成形自动控制基础课程教学协同状态进行内观和及时调整,利用教学目标达成评价结果对各班教学情况、学生学习和考核情况进行总结,推动课程团队教师采取更有效的措施,提升教学质量和水平.

将科研成果与教学内容融合,进行特色创新,拓宽学生视野,通过具体科研实例,培养运用知识解决实际问题能力.在知识传授的同时进行价值引领,通过课程中贯穿始终的思政教学,使学生具备社会责任感和工程职业道德、组织管理能力和终身学习能力等基本素质.

同步马达在多液压缸同步控制中具有广泛的应用,但由于各液压缸之间的工况差异,偶尔造成同步误差偏大且难以解决的问题.利用MATLAB建立同步马达控制四缸同步提升系统的SimHydraulics模型并进行仿真研究,通过控制变量法研究确定了同步马达控制方式下同步误差的主要影响因素,并在此基础上提出一种基于均值偏差进行换向阀流量补偿的控制策略.仿真结果表明,该控制策略能够有效消除由于工况差异造成的同步误差.

The characteristics of flow field distribution and temperature variation of an inclined jet impinging on a steel tube surface at different positions in circumferential directions were studied via numerical simulation. By analyzing the local convective heat transfer coefficient in circumferential direction, it was shown that the downstream and upstream regions had the characteristics of typical asymmetry. As the inclination angle increases, the local convective heat transfer coefficient gradually increases in the downstream region and gradually decreases in the upstream region. When the θ of the top and bottom jet is 30°, the increases in the downstream region are 40.2% and 54.6%, respectively. Based on the study of the local convective heat transfer coefficient and temperature distribution in the circumfluence direction of a steel tube during the cooling process, it was shown that the optimal inclination angle is 0~10°. With the increase in inclination angle, the average heat transfer coefficient shows a decreasing trend overall. With the increase in jet Reynolds number, the decrease in the average heat transfer coefficient gradually decreases. When the inclination angle increases to 30°, the effect of inclination angle on steel tube cooling is obviously stronger than that of jet position.

With the development of industrialization, the demand for high-performance steel materials is increasing in engineering machinery, marine engineering and other fields. As an important means to improve the performance of hot-rolled steel materials, UFC technology is widely used increasingly.1–5) It uses water jet to cool the rolled steel on the hot rolling line quickly and uniformly. It can reduce the amount of alloy elements, simplify the production process, save energy, help enterprises to reduce production costs and improve product performance.6–10) Increasing the cooling capacity can improve the production efficiency and provide powerful means for developing new types of steel. Lots of research had been done in this field. Merci11) et al. studied the effects of jet impingement height and Reynolds number on heat transfer performance. Chester and Hauksson et al.12,13) found that increasing flow rate could enhance the heat transfer ability of the hot plate surface. Öztekin et al.14) found that the increase of the roughness of the material surface will enhance the heat transfer ability. Ai et al.15) found that the use of mobile nozzles instead of fixed nozzles could improve the scour ability and enhance heat transfer. Glaspell et al.16) found that Effect of Internal Structure of Nozzle on Impingement Heat Transfer Performance of Single-beam Water Jet

The nozzle is the key component of ultra-fast cooling equipment in hot-rolling steel industry, which is crucial for improving the cooling performance. In this paper, in order to optimize the TMCP ultra-fast cooling technology, a self-excited pulsed nozzle was applied into the ultra-fast cooling equipment, and its cooling performance of jet impingement was studied. The flow states and heat transfer characteristics on the surface of the 840 degrees C steel plate, which were impinged by the conventional cylindrical convergent nozzle and self-excited pulsed nozzle formed by adding a Helmholtz oscillating chamber, were simulated by using ANSYS-Fluent under the same inlet pressure, respectively. The maximum jet velocities, dynamic pressures, outlet flow rates of the two nozzles, the temperatures and heat fluxes of the plate surface were monitored. The results showed that, under the pressure of 0.8 MPa, the average outlet flow of the self-excited pulse nozzle was lower than that of the cylindrical convergent nozzle, whilst the self-excited pulse nozzle had higher instantaneous outlet velocity and dynamic pressure. The self-excited pulsed jet could increase turbulence intensity and heat flux on the plate surface. Compared with continuous jet impingement, the self-excited pulsed jet impingement had a better heat transfer effect with lower energy input. The results of the study can provide data support for nozzle designing and better application of ultra-fast cooling equipment.

介绍了东北大学材料成型与控制工程专业人才培养目标及实践教学环节与培养目标达成的关系,项目组专业教师为实践教学环节的改革开展的"轧机仿真互动式安装软件"开发工作及实践教学形式改革的尝试;总结了"轧机仿真互动式安装软件"开发及应用效果;指出轧机装配虚拟实践教学改革对冶金类高校专业课教学改革具有示范作用.

研究了内部结构分别为柱状和锥状喷嘴的射流冲击换热性能.在初始条件和边界条件相同的情况下,利用计算流体力学软件Fluent对两种喷嘴的冲击换热过程进行了热流耦合模拟.对流固交界面的压力、剪切力、湍流强度、对流换热系数等流场和温度场数据进行对比分析.模拟结果表明,锥状结构喷嘴的射流冲击换热性能明显优于柱状结构的喷嘴.所得结论对热轧钢超快速冷却设备喷嘴的设计具有指导意义.

以满足本科生的在校学习需求、专业教学宣传为目的,开发了材料成型及控制工程专业本科教学网站.在开发过程中,注重招募学生的人才培养,尊重他们的首创精神.在校企合作过程中,通过软件公司技术培训和指导,增强了学生编辑加工网站素材能力及开发软件水平;在日常工作汇报和定期协调会议上,注重学生工程职业素养培养.通过网站开发实践,探索了人才培养模式的多样化、个性化发展途径,提高了人才培养的深度和广度.

论文介绍了材料成形机械设备课程的特点及轧机仿真交互式安装软件的功能,总结了在材料成形设备课堂教学及实验教学环节引入虚拟技术-轧机交互式仿真装配软件演示与仿真组装的效果和经验,可以为高校专业课教学提供一定的借鉴和参考.

介绍了虚拟实践教学软件项目制作过程中积累的成功经验，包括校企合作模式，校企联合培养学生模式，招募团队成功经验，第一阶段中即植入培养人的理念等。进行了大胆的尝试，培养了能够制作软件的高质量本科生，并以此作为毕业设计论文进行答辩，按照时间计划完成了软件的开发。

本文介绍了虚拟实践教学软件制作过程及挖掘本科学生潜力,提高学生技能的教学探索实践,总结了软件开发过程中积累的校企合作的成功经验.

A method was presented for the two-cylinder system to achieve high-precision synchronization by using conventional hydraulic components. Using two pumps with same displacement to drive individually two cylinders with same effective area,preliminary synchronization was achieved. With two magnetic switches detecting the synchronization error in real time,and with solenoid valves and fixed orifices,installed respectively on the high pressure pipes of the two pumps,slightly regulating the flow rates running into the cylinders,high-precision synchronization was realized. The method has been applied in a furnace feeding equipment for two years with the synchronization error controlled in 0. 4%. A detailed hydraulic principle diagram,and the flow micro-adjustment method were provided.

A highly reliable and low-cost solution was put forward to solve the poor precision problem of the conventional equal-displacement pump controlled synchronous circuit. An oil spill branch, made of a high-speed on-off valve, was added on each pump's pressure pipeline of the conventional circuit. By using the PWM (pulse width modulation) method to control each high-speed on-off valve, high-precision multi-cylinder synchronization was realized. Detailed hydraulic principle diagram and the synchronization control method were presented as well. The scheme has been used in a two-cylinder synchronous system of a mill entrance-guide device for nearly one year, with the synchronous absolute error being kept under 1.5 mm. The practical results showed that the scheme is worth promoting for its simplicity and practicality.

High speed and high accuracy synchronization control for hydraulic multi-cylinder is a difficult technical problem that must be solved before commissioning of roller-quenching machine.In order to get satisfying control result,it is usually necessary to make repeated debugging for the equipment.A simulation device for multi-cylinder synchronization was developed based on synchronous lifting principle of a roller-quenching machine's upper frame.Main functions and similarity design principle were introduced.The composition and realization method of hardware and software in computer control system were illustrated.After being fully debugging in simulation device,the control software was applied to fast-lifting control of a roller-quenching machine's upper frame with synchronous error less than 4%,and it effectively shortens the debugging period in spot.

When the fatigue behavior of a specimen is tested using an electro-hydraulic fatigue testing machine,the real load amplitude deviates from its set value as the test frequency increases,which influences the accuracy of test results directly.By measuring the real output amplitude,the difference and second difference between set and measured values of waveform were taken as the fuzzy controller's input and the compensation factor was gotten after fuzzy reasoning.After real-time correction for the waveform amplitude from the compensation factor,the accuracy of test results was improved.The inner loop PID control algorithm and the outer one were put into different threads to guarantee the real-time execution.The result shows that the method has the characteristic of high precision and rapid response,and can satisfy the high precision requirement for fatigue tests.