JPS57169596A - Heat exchanger - Google Patents

Abstract

PURPOSE:To improve the efficiency of heat transfer by fitting a plural stage of air-permeable solid walls onto the outer circumference of a heat exchanging tube in the multitubular heat exchanger. CONSTITUTION:The air-permeable solid walls 3 having air permeability and heat-resisting property are disposed rectangularly on the outer circumferences of the heat exchanging tubes 2. In this constitution, hot gas supplied from a hot gas supply port 5 is stopped and filled once at the upper stream sides of the solid walls 3 owing to the pressure loss of the air-permeable solid walls 3, is changed into an uniform current and passes through the air-permeable solid walls 3. When the hot gas passes, on the other hand, the potential heat of the hot gas moves instantaneously to the solid walls 3 because the air-permeable solid walls 3 have large convection thermal conductance, and surface temperature at the upper stream sides of the solid walls 3 rises instantaneously. Accordingly, the heat of the hot gas is directly transmitted to the heat exchanging tubes 2 while heat transmission through heat radiation transfer from the air- permeable solid walls 3 is added. Consequently, thermal conductivity can be improved properly setting the arrangement of the solid walls 3.