摘要
实验发现单微通道在高热流密度条件下会发生一种长周期/小幅度间歇性欠热沸腾现象。它发生在入口温度在室温到80℃的范围,出口温度及压差呈现非常有规律的小幅度脉动,且呈现反相。当热流密度略大于沸腾起始点时,脉动周期长达50-100 s。随着热流密度的增大,脉动周期变短。当热流密度接近临界值时,脉动周期在5-10 s。实验还发现在宽广的热流密度范围内,时均质量流速对于热流密度的变化不敏感,推断出在一个完整周期内,汽泡产生及逸出的时间相对较短。
A new type of long period/small amplitude periodic subcooled flow boiling in a heated microtube at high heat fluxes was identified. The oscillation flow is occurring at the inlet temperature ranging from room to 80℃, and behaves the small amplitude oscillations of outlet temperature and pressure drop with inverse phase. When the heat flux is just beyond that activates the boiling incipience, the oscillation time period is in the range of 50 to 100 seconds. The time period is decreased with increasing the heat flux. Such time period is around 5 to 10 seconds when the heat flux is approaching the critical heat flux. It is also identified that the mass flux in the microtube is insensitive to the applied heat flux over a wide operation range, indicating that the bubble creating and emission is a short process and covers a small percentage of the whole time period.
出处
《节能技术》
CAS
2008年第1期18-22,共5页
Energy Conservation Technology
基金
上海水产大学博士基金启动项目(6690205029)
关键词
微通道
脉动周期
脉动幅度
间歇流
micro- tube
oscillation time period
oscillation amplitude
alternative flow
