Measurement of local heat transfer and estimation of near wall adection velocity by multi-points thin film temperature sensor

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K04316
• 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: Meiji University
• Principal Investigator: Nakabeppu Osamu 明治大学, 理工学部, 専任教授 (50227873)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: MEMS / 熱流束 / 移流推定 / 乱流熱伝達 / 強制対流 / 非定常熱伝達

Outline of Final Research Achievements

In this study, we fabricated adjacent multi-point MEMS thin-film heat flux sensors and measured unsteady wall heat flux in a forced convection field. Additionally, we developed a method to estimate the advection velocity near the wall from the heat flux signals at multiple adjacent points. Over the course of four years, including a one-year extension, we prototyped four-point and five-point sensors using silicon and aluminum alloy substrates and conducted experimental studies in an air forced convection field. By analyzing the cross-correlation of heat flux, we determined the delay time between adjacent points. We developed an algorithm to calculate four surface velocity vectors for the four-point sensor and nine surface velocity vectors for the five-point sensor. By removing error vectors using the standard deviation of the calculated vectors, we established a method to obtain reliable estimated velocities.

Free Research Field

熱工学

Academic Significance and Societal Importance of the Research Achievements

エンジンやタービン，ボイラー等のエネルギー機器では，容器壁面と内部流体との熱伝達がエネルギー損失となるため，熱効率向上のためには，内平面近傍の流れと熱伝達特性を調べることが重要である。本研究成果は，レーザーや画像計測ができない容器内の流動・伝熱特性を壁面に設置した隣接多点熱流束センサで調べることを可能にする点で学術的に重要な技術である。また，エンジンの高効率化研究では，筒内の流動制御や燃料濃度の成層化制御技術が研究されており，これらを実践する上で，本研究成果が貢献することが期待される。