报告题目：Multiphase Transport Process in Conventional and Renewable Energy Systems

     传统和可再生能源系统中的多相输送过程

主讲人：徐犇博士

时间：2019年5月13日 上午10:00

地点：动力与机械学院学术报告厅B9316

Abstract:

Greenhouse gas (GHG) emission is of great significance for modern society due to the large scale civilization and industrialization in the past decades. This has led to a considerably growing attention in convention and renewable energy systems. Multiphase flow and heat transfer in these energy systems play a significant role to the system performance, such as the Thermal Energy Storage (TES) system in Concentrated Solar Power plants, the cooling system in power plants, and the desalinating of seawater and brackish water in thermal-driven desalination plants. In this presentation, we will discuss the aforementioned three topics and show how the system performance can be enhanced through multiphase flow and heat transfer analysis.

In the TES system, a corrected lumped capacitance method was developed for both sensible and latent heat storage system based on a 1D enthalpy-based transient model, and corrected heat transfer coefficients were provided for spherical, sandwiched, cylindrical and shell-and-tube configurations in TES system. Then a generalized diagram of energy storage efficiency for latent heat TES system was proposed, a series of generalized diagrams of ESE were provided for latent heat TES system, and the diagrams can serve as a convenient tool for solar thermal engineers to design and calibrate the size of TES system and operational conditions without doing complicated system level modeling and computations.

      In the second topic of dry cooling system, a comprehensive system-level analysis is performed for a novel air-cooled condenser based on spray freezing of phase change materials (PCMs). Melting of solid PCM particles in a two-phase PCM slurry flow anchors the steam condensation temperature close to the PCM melting point regardless of the change in ambient air temperature. A multiscale model, which directly captures the melting and settling of PCM particles at the microscopic level and accounts for phase change through energy source terms at the macroscopic level, has been developed to simulate the PCM slurry flow over heated tube bundles.
      

In thermal-driven desalination process, a potential negative environmental impact from the desalination process is the discharge of high concentrated brine to the environment. To avoid the potential impacts from disposing the concentrates, recovery of important minerals from concentrates to achieve zero discharge through thermal-driven evaporation is a promising option. However, the evaporation of saline droplets involves complicated multiphase heat and mass transfer, such as the formation of crust due to crystallization, the existence of insoluble particles and strong internal circulation, the classical three-stage evaporation model needs to be redefined. In the topic, we will discuss some important discoveries from some ongoing experiments and numerical modeling.

Shortbio:

Prof. Ben Xu graduated with a BS degree of Thermal Energy and Power Engineering in Wuhan University in 2007, a MS degree of Fluid Mechanics in Institute of Mechanics, Chinese Academy of Sciences in 2010, and his thesis supervisor is Prof. Jiachun Li, Academician of the Chinese Academy of Sciences. After finishing his master study, in 2010 Prof. Xu went to University of Arizona and studied with Prof. Perry Li for his doctoral research in solar thermal energy storage system. After five years study and research, Prof. Xu earned his Ph.D. in Mechanical Engineering in August, 2015, and then he joined Prof. Ying Sun’s research group in Drexel University in September 2015 as a postdoc research associate for a $3 million US DOE ARPA-E dry cooling project.

In September 2016, Prof. Xu joined the Department of Mechanical Engineering at The University of Texas Rio Grande Valley (UTRGV) as an Assistant Professor, right now Prof. Xu is the director of Multiphase Transport Lab at UTRGV, and there are two PhD students and two Master students right now in his lab.

Prof. Xu has already published more than 30 peer-revised journal papers (SCI indexed). He was the PI for a USDA funded Energy Efficiency project ($93,000), and he was the key personnel for a US NSF-MRI funded project ($230,000). Prof. Xu has been serving as the reviewer for many top journals in energy-related areas, such as Applied Energy, Energy Conversion and Management, Energy, and Renewable Energy. Prof. Xu is also serving as the Committee Sectary in the technical committee of Renewable Energy and Energy Conversion (REEC) in ASME Advanced Energy System Division.