Determination of heat transfer coefficient in a T-shaped cavity by means of solving the inverse heat conduction problem. Issue 4 (13th May 2019)

• Record Type: Journal Article
• Authors: Frąckowiak, Andrzej; Spura, David; Gampe, Uwe; Ciałkowski, Michał
• Is Part Of: International journal of numerical methods for heat & fluid flow. Volume 30:Issue 4(2020)
• Page Start: 1725
• Page End: 1742
• Publication Date: 2019-05-13
• Subjects: Heat transfer -- Cavity -- Inverse problem -- Tikhonov regularization -- Steam turbine -- Trefftz functions; Heat -- Transmission -- Mathematics -- Periodicals; Fluid dynamics -- Mathematics -- Periodicals; 536.2
• DOI: 10.1108/HFF-09-2018-0484
• Languages: English
• ISSNs: 0961-5539

Abstract

Abstract : Purpose: T-shaped cavities occur by design in many technical applications. An example of such a stator cavity is the side space between the guide vane carriers and the outer casing of a steam turbine. Thermal conditions inside it have a significant impact on the deformation of the turbine casing. In order to improve its prediction, the purpose of this paper is to provide a methodology to gain better knowledge of the local heat transfer at the cavity boundaries based on experimental results. Design/methodology/approach: To determine the heat transfer coefficient distribution inside a model cavity with the help of a scaled generic test rig, an inverse heat conduction problem is posed and a method for solving such type of problems in the form of linear combinations of Trefftz functions is presented. Findings: The results of the calculations are compared with another inverse method using first-order gradient optimization technique as well as with estimated values obtained with an analytic two-dimensional thermal network model, and they show an excellent agreement. The calculation procedure is proved to be numerically stable for different degrees of complexity of the sought boundary conditions. Originality/value: This paper provides a universal and robust methodology for the fast direct determination of an arbitrary distribution of heat transfer coefficients based on material temperature measurements spread over the confining wall.