| 摘要 |
PURPOSE:To raise the efficiency of heat transfer, by immersing an evaporation- assisting material at a portion of work fluid. CONSTITUTION:An evaporation-assisting material 3 is immersed at a portion of work fluid 2 in a gravitation type heat pipe, in particular, at a lower portion of the work fluid 2, so that the work fluid 2 is evaporated from a boundary surface A between the gas phase F and liquid phase E of the work fluid and from the lower surface of work fluid 2 by the aid of nuclei provided by the evaporation- assisting material 3. Here, bubbles B produced from the lower surface of work fluid 2 rise upward promptly by the function of buoyancy and are evaporated from the boundary surface A. Along with rising of the bubbles, turbulence is produced in the work fluid 2, so that bubbles are produced further by the turbulence. Further, the bubbles function to transmit heat at the lower portion of the work fluid to the upper portion at a higher speed than that of natural convection and to produce ripples over the boundary surface A, so that the effective evaporating area of the boundary surface can be increased. Thus, it is enabled to increase the rate of evaporation and hence to improve transmission of heat to a large extent. |
