Clarification of occurence mechanism of thermodynamic effect of cavitation by hot water experiment

2018 Fiscal Year Final Research Report

• Project/Area Number: 16H04263
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Fluid engineering
• Research Institution: Tohoku University
• Principal Investigator: Yuka Iga 東北大学, 流体科学研究所, 教授 (50375119)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: キャビテーション / 溶存気体 / 析出 / 脱気 / 熱力学的効果 / 高温水 / 極低温流体

Outline of Final Research Achievements

In order to clarify a mechanism of appearance of thermodynamic effect, in-situ measurement of dissolved gas and the control were done. From the measurement of dissolved oxygen, it was shown that liberation of dissolved gas is promoted when the unsteadiness of cavitation is strong in flow fields even with the same cavity area. This means that the localized flow acceleration and pressure fluctuations of the unsteady cavitation flow itself contributes to the liberation of dissolved gas. By adding degassed system was added which is synchronized with the in-situ measurement, dissolved oxygen ratio was kept constant though the mainstream temperature increases. Then scale effect was excluded and the thermodynamic effect was extracted.

Free Research Field

流体工学

Academic Significance and Societal Importance of the Research Achievements

キャビテーションの熱力学的効果は，LNGで顕在化する．そのガス田採取から，大量輸送のための液化，運搬船による輸送，遠隔地の受入れ基地への供給という，一連のサプライチェーンにおいて使用される多くのポンプは，実液であるLNGを用いずに設計開発され，最終的な性能確認のみLNGを用いて行われている．よって，熱力学的効果を有効に利用できておらず，キャビテーション性能（作動範囲）に余裕のある設計となっていると想像できる．熱力学的効果を最適化できれば，高性能ポンプを用いたインフラ整備によって，一連のLNGサプライチェーンの低コスト化が実現し，安全・安心なクリーンエネルギーの普及が加速される．