Development of mixed state evaporation coefficient measurement method based on acoustic resonance tube experiment and establishment of experimental formula

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K21576
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Fluid engineering; Thermal engineering
• Research Institution: Nara National College of Technology
• Principal Investigator: Nakamura Shigeto 奈良工業高等専門学校, 電子制御工学科, 講師 (80619867)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 蒸発 / 凝縮 / 蒸発係数 / 相変化 / 凝縮係数 / 共鳴音波 / 分子気体力学

Outline of Final Research Achievements

The purpose of this project is to develop the measurement method for evaporation coefficient corresponding to the mixed state based on the method using the resonant sound wave and construct the experimental formula to easily and accurately determine the evaporation coefficient.
The introduction of the sample vapor tank and the sample liquid film tank eliminated the influence of non-condensable gas. And this introduction possible to realize the mixed state with high accuracy. After the experimental equipment was improved, the evaporation coefficient was measured for water, and it was confirmed that it was about 1.0 at around 300 K as before the improvement.
The experimental formula for determining the evaporation coefficient has not been established due to the influence of the electromagnetic noise generated from the sound source, but we continue to work on the reduction of the influence of the electromagnetic noise for realization.

Free Research Field

分子流体力学

Academic Significance and Societal Importance of the Research Achievements

実際の現象を考えた場合，単一の試料物質のみから構成される系より，複数の物質が混合した系（混合状態）の方が，数多く存在する．一方，現状ではこのような混合状態に対応した蒸発係数測定法は存在せず，混合状態が蒸発係数にどのような影響を及ぼすのか，明らかとなっていない．また蒸発係数を決定するための実験式が構築されれば，実験をすることなく蒸発係数を求めることが可能となる．蒸発係数を正確に決定することは，単に現象の解析にとどまらず，熱交換器，薄膜形成など，蒸発，凝縮が関わる技術において，より効率的な制御を可能とする．加えて異常気象，地球温暖化など気象分野に対しても，より正確な現象の予測が可能となる．