Numerical and experimental study of electromagnetic induction heating process for bolted flange joints

Author(s):  
Zhufeng Liu ◽  
Yonghui Xie ◽  
Xiaolong Ye ◽  
Jun Wang ◽  
Bin Liu

As a promising metalwork processing technology, electromagnetic induction heating (EMIH) method has been applied in dealing with bolted flange joints in turbomachinery. In this study, a 3-D finite element model of electromagnetic induction heating system for the bolted flange joint is established, and the specific governing equations are derived based on Maxwell’s principle. The alternately-coupled magneto-thermal analysis is carried out considering temperature-dependent material properties to obtain the temperature distribution, followed with the uncoupled thermal-mechanical analysis to acquire the axial stress and deformation in EMIH process. The magnetic induction intensity mainly concentrates at the inner wall region, attenuates seriously along the radial direction, and reduces to almost zero at the outer wall. Due to the skin effect, the heat transfers radially and axially outward, indicating a diamondlike-shaped development from the center to the surrounding region. The axial stress with and without initial pretension are also discussed respectively. Then the corresponding experiments are introduced and carried out to validate the reliability of numerical simulation results. By comparing the results of the center point of inner surface and outer surface, the numerical simulation is proved reliable with a 5∼10% reasonable deviation. Further, the induction heating process has been improved through the optimization method based on pattern search algorithm. By adopting the stepped input current density optimized in the study, the optimal thermal stress tends to be constant and the final heating time reduces by 20.5% in the safe range of stress.

2020 ◽  
Vol 10 (7) ◽  
pp. 2304
Author(s):  
Lichun Chang ◽  
Yao Zhao ◽  
Hua Yuan ◽  
Xiaocai Hu ◽  
Zhen Yang ◽  
...  

Line heating is an essential process in the formation of ship hull plates with a complex curvature. Electromagnetic induction heating is widely used in the line heating process. In electromagnetic induction heating, the shape of the coil and the air gap between the inductor and workpiece could influence the heat source distribution. Moreover, in the line heating process, the change of curvature of the plate will cause a change of the air gap of the inductor. Magnetic thermal coupling calculation is an effective method for simulating induction heating. This paper used the finite element method to calculate the distribution of heat sources in different initial plate curvatures and coil widths. The changes in heat source distribution and its laws were investigated. The results show that when the coil width is less than 100 mm, the effect of plate curvature on heat source distribution and strain distribution is not apparent; when the coil width is greater than 100 mm, the plate curvature has a visible effect on the heat generation distribution. In the case of a curvature increasing from 0 to 1 and a coil width equal to 220 mm, the Joule heat generation in the center of the heating area is reduced by up to 21%.


Author(s):  
Jiaxin Wang ◽  
Qiang Lv ◽  
Zhiyin Gan ◽  
Sheng Liu

This paper introduces an innovative method using high-frequency electromagnetic induction heating to realize a partial heating process without increasing overall chip temperature. This method provides an easy and reliable way to solve the long-term problem that has limited carbon nanotube application in mass integrated circuit production. Carbon nanotube alignment and bonding experiments are also conducted and the results are analyzed and discussed. The results show that the resistance of the carbon nanotube–metal interface reduces by 90% after bonding and the contact of the interface exhibits excellent endurance.


Author(s):  
Arnulfo Pérez-Pérez ◽  
Jorge Sergio Téllez-Martínez ◽  
Gregorio Hortelano-Capetillo ◽  
Jesús Israel Barraza-Fierro

In this work, the dimensions of a furnace for melting of ferrous alloys were determined. The furnace has an electromagnetic induction heating system. In addition, the parameters of electrical power supply such as frequency and power were calculated. A 5kg cast steel mass with a density of 7.81 kg / dm3 was proposed. This corresponds to a crucible volume of 0.641 dm3. The frequency was obtained from tables, which take into account the diameter of the crucible, and its value was 1 KHz. The energy consumption was determined with the heat required to bring the steel to the temperature of 1740 K, the energy losses through the walls, bottom and top of the crucible. This value was divided between the heating time (30 minutes) and resulted in a power of 4.5 KW. The development of the calculations shows that the induction heating is an efficient process and allows a fast melting of ferrous alloys.


2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Christian W. Müller ◽  
Ronny Pfeifer ◽  
Karen Meier ◽  
Sebastian Decker ◽  
Janin Reifenrath ◽  
...  

Nickel-titanium shape memory alloy (NiTi-SMA) implants might allow modulating fracture healing, changing their stiffness through alteration of both elastic modulus and cross-sectional shape by employing the shape memory effect (SME). Hypotheses: a novel NiTi-SMA plate stabilizes tibia osteotomies in rabbits. After noninvasive electromagnetic induction heating the alloy exhibits the SME and the plate changes towards higher stiffness (inverse dynamization) resulting in increased fixation stiffness and equal or better bony healing. In 14 rabbits, 1.0 mm tibia osteotomies were fixed with our experimental plate. Animals were randomised for control or induction heating at three weeks postoperatively. Repetitive X-ray imaging and in vivo measurements of bending stiffness were performed. After sacrifice at 8 weeks, macroscopic evaluation,µCT, and post mortem bending tests of the tibiae were carried out. One death and one early implant dislocation occurred. Following electromagnetic induction heating, radiographic and macroscopic changes of the implant proved successful SME activation. All osteotomies healed. In the treatment group, bending stiffness increased over time. Differences between groups were not significant. In conclusion, we demonstrated successful healing of rabbit tibia osteotomies using our novel NiTi-SMA plate. We demonstrated shape-changing SME in-vivo through transcutaneous electromagnetic induction heating. Thus, future orthopaedic implants could be modified without additional surgery.


2018 ◽  
Vol 168 ◽  
pp. 02004
Author(s):  
Richard Lenhard ◽  
Milan Malcho ◽  
Katarína Kaduchová

In the paper is shown the connection of two toolboxes in an Ansys Workbench solution for induction heating. In Ansys Workbench, Maxwell electromagnetism programs and Fluent have been linked. In Maxwell, a simulation of electromagnetic induction was performed, where data on the magnetic field distribution in the heated material was obtained and then transformed into the Fluent program in which the induction heating simulation was performed.


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