上海交通大学張鵬教授（Prof. Peng Zhang）の講演会が開催されます
Last Update 2010.11.18
日時：2010年12月14日13:30 - 15:30
演題：Flow and heat transfer characteristics of TBAB CHS for cold storage（臭化テトラn- ブチルアンモニウム水和物スラリの熱流動特性）
概要：TBAB CHS (tetra-n-butylammonium bromide clathrate hydrate slurry) is believed to be a good candidate as the secondary refrigerant, and the consequent merits for such system are that both reduction of conventional refrigerant and cold storage can be easily achieved; as a result, the environmental protection from CFC and HCFC and energy conservation are realized simultaneously. TBAB CHS is good for its appropriate temperature range (5-12 ℃) and large latent heat, which spurred many applications in air conditioning. Nevertheless, the hydraulic and thermal characteristics of TBAB CHS are still rarely known, which are evidently important for its further application in energy systems. In the first presentation, the force flow and convective melting of TBAB CHS in the circular tube will be discussed. The generation of TBAB CHS and cold storage system by TBAB CHS are also introduced. The estimation indicates that high energy efficiency and cost-saving of the air-conditioning system can be achieved by TBAB CHS cold storage.
日時：2010年12月15日9:30 - 11:30
演題：Flow boiling of liquid nitrogen in mini/micro-tubes（ミニ／マイクロチューブ中における液体窒素の流動沸騰）
概要：In the second talk, investigation of flow and heat transfer characteristics of liquid nitrogen in mini/micro-tubes will be presented. The small viscosity enables the flow state in mini/micro-tubes to be turbulent state, which proves that the classical theory for pressure drop is still valid if the roughness of the passage is properly taken into consideration. Experiments of flow boiling of liquid nitrogen were conducted under both adiabatic and diabatic conditions. It is shown that confinement number Co=0.5 can be applicable in classifying the heat transfer characteristics of liquid nitrogen in macro- and micro-channels. Flow visualization in micro-channels at low temperatures poses big challenges in image magnification and illumination. These two problems have been subtly overcome in our investigation and clear images have been obtained. The flow patterns and flow regimes of two-phase nitrogen flow present different features. Furthermore, we proposed and implemented a very simple but effective method for 3D flow visualization by one high-speed camera. Finally, numerical analysis of the flow boiling of liquid nitrogen in mini/micro-channel was carried out to deepen the understanding of mechanism.