熱音響エンジンの発生音波に及ぼすスタック位置の影響

application/pdfA thermoacoustic engine is a equipment which changes heat into acoustic sound. If this equipment is realized, it can be used as a power source of a thermoacoustic refrigerator. We made a resonance pipe engine and tried to verify its operation. A stack, which serves as a heat storage element, was inserted in a resonance pipe. Various attempts were made to produce stable acoustic sound, by changing total pipe length, stack position in the pipe, and temperature difference between the stack ends. Generation of unsteady acoustic sound was obtained when the beginning of cooling the high temperature stack. It is suggested by an experiment of that the suitable position of the stack is in between the displacement node and antinode of a sound wave

水-空気系泡沫流れの不連続流体モデル

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多段式共鳴管冷凍機における蓄冷器の最適位置

application/pdfA thermoacoustic refrigerator is a equipment that pumps up heat by acoustic sound. A resonance pipe refrigerator, which is one of thermoacoustic refrigerators, has many advantages, such as compact, simple structure, no moving parts, and so on. We made a resonance pipe refrigerator and verified its operation. A stack, which serves as a heat storage element, was inserted in the resonance pipe. Temperature difference of the stack ends, was measured by changing location of the stack in the pipe. It is indicated that the suitable position of the stack is in between pressure node and antinode of sound wave. Possibility of multi-stack operation is also discussed

円管内を流動する液体泡沫の圧力降下と熱伝達

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管内を流動する液体泡沫の壁面せん断応力

application/pdfAn experimental study was conducted on the pressure drop for foam flow through a rectangular/circular pipe. Foam flow in a pipe was approximated by a model in which foam is lubricated by a thin layer of a Newtonian liquid (slip-layer) on the pipe wall. Indirect measurement of the slip-layer shows that its thickness depends on the flow velocity. Experimental equations for the slip-layer thickness were determined. A power-law equation with a yield shear-stress was used as the rheological equation for the foam flowing over the liquid-slip layer. Values of the parameters included in the equation were experimentally determined. Prediction of the wall shear stress for foam flow in a pipe can be possible by using these equations