High-precision liquid-phase speed of sound and density measurement for optimizing the equation of state of next-generation refrigerants

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K03903
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 19020:Thermal engineering-related
• Research Institution: Fukuoka University
• Principal Investigator: Nishiyama Takashi 福岡大学, 工学部, 助教 (80363381)
• Co-Investigator(Kenkyū-buntansha): 高尾 幸来 福岡大学, 工学部, 教授 (50234688)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 次世代冷媒 / 低GWP冷媒 / 液音速測定 / 液密度測定 / 状態方程式

Outline of Final Research Achievements

In addition to the high-precision liquid-phase speed of sound measurement based on the equation of state of the low-GWP refrigerant R-1336mzz(Z) that the applicants have established, the research aimed to measure the liquid-phase density as well as a wider temperature range speed of sound measurement, because it is desirable to obtain multiple thermophysical property information for the same sample. As a result, we were able to achieve high accuracy up to 125°C, which is the upper limit of speed of sound sensor measurement, by correcting the effect of sound wave absorption in the range above 100°C, which was initially difficult to achieve. Furthermore, the accuracy of the liquid-phase density measurement was also improved by adding the value obtained when the vibrating tube of the densimeter was evacuated as a calibration standard, in addition to the reference material used for the conventional calibration.

Free Research Field

熱工学

Academic Significance and Societal Importance of the Research Achievements

地球温暖化対策は急務であり、エアコン等に用いられる冷媒についても、温暖化に寄与しないものが求められている。次々に提案される次世代冷媒の候補物質を評価・使用するにあたり、それぞれの熱物性を測定して高精度な状態方程式（EOS）を作成せねばならないが、それらの熱物性測定を行える拠点は世界的にも限られている。
本研究によって実現した液相音速・液相密度測定では、すべて市販のセンサー類を用いているため比較的容易に取り組むことができる内容でありながら、EOS作成に求められる精度も達成できるため、今後の新規EOS作成において十分に役立つと考えらる。