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沸腾现象及其曲线特性

今日出厂产品展示及部分报价

1、 沸腾现象及其曲线特性
1, the boiling phenomenon and its characteristics
加热器沸腾现象的实验装置,在这个装置中,若经热流密度控制器控制,对加热器施加较低的功率时,加热器产生较低的热流密度,经一段时间后,在液面可以看到有蒸汽产生,而当热流密度控制器对加热器施加较大功率时,液面上除看到产生的蒸汽外,加热器的表面会产生气泡,这些气泡在脱离加热器表面层浸入液体并上升,上升过程中气泡体积也将进一步发生变法,这种伴随气泡生产的过程称为沸腾或气泡的生成
The experimental device of heater boiling phenomenon, in this system, if the heat flux controller, applied to low power of heater, heater to generate heat flux density low, after a period of time, can be seen in the liquid level of steam is generated, and when the heat flux controller applied to large power heater, liquid level in addition to see the steam, the heater surface will produce bubbles, the bubbles and rise from the heater surface layer is dipped into the liquid, the bubble volume will also further political reform in the rising process, which is called the bubble with boiling or bubble production generation
在分析问题时,我们先说明一个专用名词,过于温度。
In analyzing the problem, we first illustrate a specific term, over temperature.
所谓过余温度,就是加热器表面温度与液体的沸点温度之差值。过余温度的大小对研究沸腾及电热元件的使用有极其重要的现实意义。
The so-called excess temperature, is the temperature and the boiling point of the liquid heater surface temperature difference. Has the extremely important practical significance to use excess temperature of boiling and the size of the heating element.
容器沸腾的曲线特征图区域划分图
Figure area partition curve containers of boiling
在以上曲线图示中,已经将容器底部加热的液体沸腾状态过程图全部描述出来了现开始对每一区域特征作文字性的说明及解释:
In the above diagram, the bottom of the container is heated in boiling liquid state of all description out now on each region characteristic word of description and explanation:
首先对I区的自然对流现象作定性描述:自然对流的产生本质是流体因密度变法而产生的浮力作用而运动的,因此,当底部输入的微小功率作用于发热元件而产生的微热而导致底部界面液体的密度而减小所产生的一种自然对流的导热现象,这是一种宏观无法直觉的过度状态。
First, natural convection in the I area of the phenomenon of qualitative description: produce the essence of natural convection is due to buoyancy fluid density method of motion, therefore, density and decrease is the result of a natural convection heat conduction phenomenon when the small power input to the bottom of the heating element and the heat caused the bottom the interface of liquid, which is a kind of excessive state macro cannot intuition.
II区:当底部加热元件的输入功率产生的热量导致界面液相转化后的气相(气泡)在上升过程中合聚并快速上升致自由表面,并形成宏观上的气泡柱。
II: input power when the bottom heating elements heat generation resulting in interfacial liquid phase transformation after the gas phase (bubble) in the rising process together and quickly rise to the free surface, and the formation of bubble column on macroscopic.
IV区:当底部加热元件面与液体结合的界面完全被气泡所隔绝,形成的气膜使得热阻加大,减小了加热元件与液体的热交换速率,这种气泡的出线,相对于加热元件的热扩散过程来说,无疑是热阻增加的一种事实存在。在此过程中,传递速率随过余温度的增加而减小,而且在这过程中还存在脉动现象:由于气膜的破裂和重新出现是随机,所以此过程也是一个很不稳定的工程。
IV: when combined with the bottom heating element surface and the liquid interface was completely cut off gas bubbles, film forming the resistance increase, reduce the heating element and liquid heat exchange rate, outlet this bubble, with respect to the thermal diffusion process heating element, is a fact that there is thermal resistance increase. In this process, increase the transfer rate increases as the excess temperature and reduced, but also the existence of pulsation phenomena in this process: due to the rupture of gas film and re appear to be random, so this process is a very unstable engineering.
V区:当加热元件表面上的气膜变得稳定是,即△T达到约400℃时,辐射传热现象并主导着传热的方式。所以,此时的热流密度再次随△T之增大而增大。
V area: when the heating element on the surface of the film becomes stable, namely the △ T at about 400 ℃, radiation heat transfer phenomena and dominate the heat transfer method. Therefore, heat flux density at this time again with △ T increased.
VI区:在此时,加热面的传热方式主要由辐射方式来完成或者辐射方式的传热占总传热量的绝大对数。
VI: at this time, the heat transfer heat transfer by radiation heating surface to complete or radiation mode of total heat transfer the vast majority of the number of.

高温炉|退火炉|隧道炉|陶瓷加热器|加热管

高温炉|退火炉|隧道炉|陶瓷加热器|加热管

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