Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
COMMISSIONING OF AN EXPERIMENTAL BENCH TO DETERMINE THE INTERNAL HEAT TRANSFER COEFFICIENT IN ROTATING TUBES DURING THE QUENCHING PROCESS
Submission Author:
Kássio Nogueira Cançado , MG
Co-Authors:
Kássio Nogueira Cançado, PEDRO HENRIQUE VASCONCELLOS APIPE, Willian Moreira Duarte, Luiz Machado, Ricardo Junqueira Silva
Presenter: Kássio Nogueira Cançado
doi://10.26678/ABCM.COBEM2021.COB2021-0786
Abstract
The objective of this work is the presentation and commissioning of a test bench for experimental determination of the heat transfer coefficient between the internal surface of a steel pipe and water jets in similar conditions verified during the quenching process. This treatment aims to improve certain mechanical properties of steel, including increases in the hardness of the material and its yield strength. In general, the quenching process is carried out by immersing the heated tube under conditions of rotating in a water tank in association with an internal jet of water. During the water flow through the tube, the fluid is heated by the hot walls, becoming a liquid / vapor two-phase mixture. The final quality of the product depends on several parameters that affect the cooling rate of the tube, such as the immersion time and the rotation speed of the tube. Mathematical models can be used to simulate various tube cooling conditions during the quenching, but their reliability depends significantly on the uncertainties related to heat transfer coefficients used in the energy balance equations. The relevance of the present study comes from the lack of correlations in the literature to calculate these coefficients in the conditions of quenching process. For effects of commissioning the experimental bench in the present work, the tests were performed in a tube with a rotation range of 0-100 RPM that operated internally, sometimes with water other with vapor. The results were compared with theoretical values obtained through the few correlations available in the literature. For the static tube, in which the correlations presented in the literature are more established, the experimental and theoretical results showed good agreement, with average deviations of 14% for vapor and 28% for liquid state, indicating that, the experimental bench and the methodology used in the tests may be extended for studies with rotating tubes and subjected to two-phase internal flow typical in the quenching process.
Keywords
quenching, Rotating tubes, Heat transfer coefficient, Experimental Study, Commissioning
