熱伝熱に及ぼす超音波の影響

概要

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This paper reports the results of an experimental investigation of the effect of the ultrasonic vibration on the heat transfer to the water flowing in tube.　A vertical concentric-tube heat exchanger with 3.56 cm I.D. copper tube inside a 4.95 cm I.D. Acrylate tube is used. The water flowing through the inner tube is heated by the hot water flowing through the annulus.　The exchanger is thermally insulated from the atmosphere. Inner tube (copper tube) has a length of 64 cm and an entrance region length of 120 cm.　The tube wall temperature is determined by means of thermister placed at constant intervals on the tube. Calibrated Beckmann thermometers are used to measure the temperatures of the water at inlet and outlet.　The ultrasonic vibrator having a frequency of 20 Kc/sec to supply vibrational energy to the fluid is mounted on the top of the inner tube.　The increase in an average heat transfer coefficient is about 27 per cent for laminar flow and about 10 per cent for transition region and turbulent flow.　The effect of ultrasonic vibration on heat transfer is presented by plotting the data taken in terms of Re vs. Nu Pr^(μ_a/μ_w)^.　This result is similar to the Sieder-Tate's correlation.
山形大学の論文
1969-03-20