Abstract: A forced oscillatory flow type heat pipe of which a ratio (motion coefficient) of the heat transport capacity to the oscillating energy is maintained within an appropriate range is provided. A heat pipe body (1) has a closed loop flow path (2). Operation of the vibrator (3), which is provided at a connecting portion (2a) between the ends of the flow path (2), causes an oscillatory flow of the charged liquid sealed in the flow path (2). The phases of the oscillatory flows of the charged liquid in the adjacent tube portions of the flow path are inverted. From a viewpoint that the dimensionless effective thermal diffusivity kef* of the COSMOS type heat pipe has a larger range in the modified Womersley number &agr; than that of the dream type heat pipe, the modified Womersley number &agr; is 0.4 to 7.

Abstract: A forced oscillatory flow type heat pipe of which a ratio (motion coefficient) of the heat transport capacity to the oscillating energy is maintained within an appropriate range is provided. A heat pipe body (1) has a closed loop flow path (2). Operation of the vibrator (3) , which is provided at a connecting portion (2a) between the ends of the flow path (2), causes an oscillatory flow of the charged liquid sealed in the flow path (2). The phases of the oscillatory flows of the charged liquid in the adjacent tube portions of the flow path are inverted. From a viewpoint that the dimensionless effective thermal diffusivity kef* of the COSMOS type heat pipe has a larger range in the modified Womersley number &agr; than that of the dream type heat pipe, the modified Womersley number &agr; is 0.4 to 7.