Lei Zhao

This book concentrates on high-fidelity numerical methods for predicting internal flows within aeroengines’ compressors. A distinctive features of this work is the establishment of a comprehensive research framework. Specifically, it starts with engineering application requirements and integrates high-performance parallel algorithms to develop detached eddy simulation (DES)-series methods tailored to the needs of compressor design. Additionally, it encompasses the development of data analysis methods suitable for handling the "vast" amounts of high-fidelity unsteady flow data in compressors and the high spatial resolution experimental results. This book takes us from making the intricate details of compressor flow field structures "visible" to “explainable”. Another noteworthy aspect of this book is its practical orientation, seamlessly intergrating theoretical concepts with practical applications. Herein, it addresses three major engineering problems in detail and elucidates the technical approaches involving advanced numerical methods and data analysis techniques for solving these physical problems. The book highlights the challenging issues associated with complex internal flows in compressors, the governing equations for DES-series methods, and the implementation strategies for numerical simulations of internal compressor flows. They also delve into data-driven analysis methods for unsteady flow field data, high-fidelity numerical simulations of flow in the blade root region of compressors, dynamic flow capture methods in the tip region of compressor blades, and simulation and analysis of flow fields in inlet distortion generators. This book serves as a valuable reference for researchers and engineering professionals in the aerospace, computational fluid dynamics, and high-performance turbomachinery fields. Additionally, it can be used as a specialized textbook for doctoral and master's students in disciplines such as aerospace science and technology, power engineering, and engineering thermophysics.

Taking high-speed PMSMs as the research object, in-depth study of control system has become an important part of industrial development. The main strategy used in high-speed PMSMs is the vector control system. The rotor position angle is precisely calculated through the control algorithm, thereby improving the operational stability of the system. However, the commonly used mechanical rotor position sensor not only increases the design cost of the vector control system, but also reduces the rotor position observation accuracy and reduces the reliability of the operating system. Using an algorithm to estimate the rotor angle requires the control system to collect accurate three-phase currents, decouple them according to coordinate transformation, and finally estimate the rotor position angle of the permanent magnet synchronous motor by expanding the back electromotive force. Commonly used rotor position detection methods include: sliding mode observer method, model reference adaptive method, and high-frequency signal injection method. For PMSMs with different speeds and different performances, the different algorithms used to observe the rotor position will have different accuracy.

Inorganic Geochemistry of Coal explains how to determine the concentrations and modes of occurrence of elements in coal, how to diminish adverse effects of toxic elements on the environment and human health, which elements in coal could be industrially utilized, and which elements can be successfully used as indications for deciphering depositional environments and tectonic evolution. As coal use will remain at an all-time high for the next several decades, there is a critical need for understanding the properties of this fuel to ensure efficient use, encourage its economic by-product potential, and to help minimize its negative technological, environmental and health impacts.

This book concentrates on high-fidelity numerical methods for predicting internal flows within aeroengines’ compressors. A distinctive features of this work is the establishment of a comprehensive research framework. Specifically, it starts with engineering application requirements and integrates high-performance parallel algorithms to develop detached eddy simulation (DES)-series methods tailored to the needs of compressor design. Additionally, it encompasses the development of data analysis methods suitable for handling the "vast" amounts of high-fidelity unsteady flow data in compressors and the high spatial resolution experimental results. This book takes us from making the intricate details of compressor flow field structures "visible" to “explainable”. Another noteworthy aspect of this book is its practical orientation, seamlessly intergrating theoretical concepts with practical applications. Herein, it addresses three major engineering problems in detail and elucidates the technical approaches involving advanced numerical methods and data analysis techniques for solving these physical problems. The book highlights the challenging issues associated with complex internal flows in compressors, the governing equations for DES-series methods, and the implementation strategies for numerical simulations of internal compressor flows. They also delve into data-driven analysis methods for unsteady flow field data, high-fidelity numerical simulations of flow in the blade root region of compressors, dynamic flow capture methods in the tip region of compressor blades, and simulation and analysis of flow fields in inlet distortion generators. This book serves as a valuable reference for researchers and engineering professionals in the aerospace, computational fluid dynamics, and high-performance turbomachinery fields. Additionally, it can be used as a specialized textbook for doctoral and master's students in disciplines such as aerospace science and technology, power engineering, and engineering thermophysics.