직렬 4원주 주위의 유체유동 및 열전달에 관한 실험적 연구

Abstract

Heat exchangers are commonly used in practice in a wide range of application, from heat and air-conditioning system in a household, to chemical processing and power production in large plant. An Experimental study was conducted to investigated the fluid flow and heat transfer around four circular cylinders of in-line in a cross flow of air. The local and average heat transfer characteristics for tube banks are investigated in the present study. Heat transfer in a heat exchanger usually involves convection in each fluid and conduction through the wall separating the two fluid. The in-line pitch ratio was in the range 1.5≤L/d≤4.0, where L is the center distance and d the cylinder diameter, and in the Reynolds number 8,000≤Re≤50,000. The local and mean Nusselt numbers were estimated. Subsequently, the heat transfer characteristics of four circular cylinders are found to exhibit a strong dependency upon the separation point of their upstream cylinders.