The public defense of MD Lokman Hosain's doctoral thesis in Energy and Environmental Engineering

Doctoral thesis and Licentiate seminars

Datum: 2018-12-14
Tid: 13.00 - 16.00
Plats: MDH, room Delta, Västerås

The public defense of MD Lokman Hosain's doctoral thesis in Energy and Environmental Engineering will take place on MDH on December 14.

The public defense of MD Lokman Hosain's doctoral thesis in Energy and Environmental Engineering will take place at Mälardalen University, room Delta (Västerås Campus) at 13.00 on December 14, 2018.

The title of the thesis: “Fluid Flow and Heat Transfer Simulations for Complex Industrial Applications: From Reynolds Averaged Navier-Stokes towards Smoothed Particle Hydrodynamics”.

Serial number: 282

The faculty examiner is Professor Moncho Gomez Gesteira, University of Vigo, and the examining committee consists of Professor Britt Moldestad, USN University of South-Eastern Norway; Associate Professor Anestis Kalfas, Aristotle University of Thessaloniki; Professor Jamel Chahed, University of Tunis El Manar.

Reserve: Professor Anatoliy Malyarenko, Mälardalen University

Summary

The energy demand and environmental impacts from the industrial sector are growing concerns within the European Union (EU) due to the need to comply with the strict energy and environmental policy. Optimal process control can significantly enhance energy efficiency of heating and cooling processes in many industries. Process control systems typically rely on measurements and so called grey or black box models that are based mainly on empirical correlations, in which the transient characteristics and their influence on the control parameters are often ignored. A robust and reliable high-fidelity numerical technique, to solve fluid flow and heat transfer problems, such as computational fluid dynamics (CFD), which is capable of providing a detailed understanding of the multiple underlying physical phenomena, is a necessity for optimization, decision support and diagnostics of complex industrial systems. There are several different options within CFD methods and tools, however, choosing the right numerical tool to solve advanced engineering problems, and particularly in industrial research and development (R&D) is often difficult, and the consequences of choosing the wrong tool can be very costly. This thesis deals with several energy-intensive complex industrial applications. The goal is to identify the difficulties and challenges to be met when simulating these applications using different CFD tools and methods and to discuss the strengths and limitations of the different tools.

The thesis focuses on performing high-fidelity CFD simulations of a wide range of industrial applications to highlight and understand the complex nonlinear coupling between the fluid flow, heat transfer and other phenomena inherent to the investigated processes, e.g. combustion or induced transients. The industrial applications studied in this thesis include the runout table (ROT) cooling process and slab reheating furnace in a hot rolling steel plant, rotating machines such as electric motors and generators, heat exchangers and sloshing inside a ship carrying liquefied natural gas (LNG). The mesh-based finite volume CFD solver ANSYS Fluent is employed to acquire detailed and accurate solutions of each application and to highlight challenges and limitations. The limitations of conventional mesh-based CFD tools are exposed when attempting to resolve the multiple space and time scales involved in large industrial processes. They are not capable of addressing the multiple jet impingement on a fast-moving strip that we encounter in the ROT cooling process, and are often only partly successful, as in the slab reheating furnace. Therefore, a mesh-free particle method, smoothed particle hydrodynamics (SPH) is identified in this thesis as an alternative to overcome some of the observed limitations of the mesh-based solvers. SPH is introduced to simulate some of the selected cases to understand the challenges and highlight the limitations.        

The thesis also contributes to the development of SPH by implementing the energy equation into an open-source SPH flow solver to solve thermal problems. The comparison between the solutions from finite volume and SPH methods presented in this thesis clearly indicates their strengths and limitations for different types of problems. The thesis highlights the current state of different CFD approaches towards complex industrial applications and discusses the future development possibilities.

The overall observations and the hypothesis, based on the industrial problems addressed in this thesis, can serve as decision tool for industries to select an appropriate numerical method or tool for solving problems within the presented context. The analysis and discussions also serve as a basis for further development and research to shed light on the use of real-time CFD simulations for improved process control, optimization and diagnostics.