1989 Fiscal Year Final Research Report Summary
Clarification of the Mechanism of Thermal Diffusion due to the Fluctuation of Large Scale in a Three-dimensional Opposed Jet
| Project/Area Number |
63550164
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Thermal engineering
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| Research Institution | Nagoya University |
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Principal Investigator |
YAMASHITA Hiroshi Nagoya Univ., Mechanical Engng., Associate Professor, 工学部, 助教授 (40111835)
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| Co-Investigator(Kenkyū-buntansha) |
KAGA Sadamu Nagoya Univ., Mechanical Engng., Research Associate, 工学部, 助手 (20023096)
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| Project Period (FY) |
1988 – 1989
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| Keywords | Opposed Jet / Large-Scale Fluctuation / Heat Transfer / Diffusion / Three-dimension / Flow Visualization / Numerical Analysis / Laser-induced Fluorescence |
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| Research Abstract |
1. The experiment in an air jet The fluid flow and heat transfer in an opposed axisymmetric jet in a uniform stream were investigated, being paid attention to the unsteady motions for jet velocity 10-45m/s and uniform stream velocity 5-15m/s. An air jet heated to a temperature of about twenty degrees above a uniform air stream issues from a nozzle 5.0mm in diameter. Time histories and power spectra of velocity and temperature are measured by a hot-wire anemometer, a resistance thermometer and a FFT spectrum analyzer. These indicate that there are unsteady motions of low frequency and large scale, the frequencies of which are varied with the distance from the nozzle exit and the velocity ratio. The results may be well rearranged in terms of jet-reached distance, that is, the distance between the nozzle exit and the flow stagnation point.
2. The experiment in a water jet The experimental method which enables instantaneous and quantitative detection of two-dimensional concentration field by the laser-induced fluorescence was established, and the fluid flow and turbulent mixing in an axisymmetric jet developed in a co-flowing stream was investigated by using the present experimental method. A water jet mixed with an extremely small quantity of fluorescein sodium issues from a round injector 6.0mm in diameter with the jet velocity 0.04-0.48m/s. A co-flowing uniform water stream velocity is 0.04m/s or 0.08m/s. The intensity of fluorescence induced by an argon ion laser with relatively low output power was so high to enable instantaneous and quantitative detection of two-dimensional concentration field. The mechanism of the transition from laminar to turbulent flow and turbulent mixing was made clear.
3. The development of programme for numerical analysis The programme was made to solve the time dependent three-dimensional Navier-Stokes equation and energy equation by using a finite difference method.
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Research Products
(2 results)
