【摘要】：隨著經(jīng)濟的快速發(fā)展,工業(yè)建筑室內(nèi)污染問題日益突出。工業(yè)生產(chǎn)過程中散發(fā)的各種有害物以及余熱余濕,使得工人的作業(yè)環(huán)境十分惡劣,嚴重危害操作人員的健康。局部送風(fēng)是一種節(jié)能的通風(fēng)方式,對于操作崗位固定的高大工業(yè)建筑,尤為適宜采用局部送風(fēng)方式對工人工作區(qū)進行重點控制,可有效改善工作區(qū)的局部微環(huán)境、降低能耗。在工業(yè)建筑中,經(jīng)常存在高強度熱源,由熱源引起的自然對流、人的熱羽流以及局部送風(fēng)強迫對流耦合作用下的氣流規(guī)律特性尚不明晰,限制了局部送風(fēng)系統(tǒng)在工業(yè)建筑中的應(yīng)用。為了提高局部送風(fēng)系統(tǒng)的性能、降低能耗,有待于對此混合對流的流動機理及混合對流的流動特性和熱特性進行深入地研究與探討。論文研究有高溫?zé)嵩磿r,頂送風(fēng)方式下的工作區(qū)局部微環(huán)境控制。首先,研究了送風(fēng)射流與面源羽流相向作用下的的混合對流流動規(guī)律。通過實驗與數(shù)值模擬的方法研究了射流送風(fēng)速度、送風(fēng)溫度,熱源強度、熱源尺寸,背景溫度對混合對流流場的影響。發(fā)現(xiàn)了混合對流的流動特征:射流與羽流的“相斥”現(xiàn)象,即射流與羽流相互排斥并遠離;射流向羽流方向偏轉(zhuǎn);在高強度羽流作用時射流失效(不能覆蓋工作區(qū))。揭示了其相應(yīng)的流動機理:(1)射流較弱時,射流與羽流相向流動,在共同作用區(qū),速度下降,壓強增加;而射流與羽流另一側(cè),由于卷吸使得其外側(cè)速度增加,壓強降低;從而產(chǎn)生導(dǎo)致相斥流動的壓強差。射流較強時,射流沖擊地面后射流動量轉(zhuǎn)向,進而推擠羽流。(2)射流向羽流方向偏轉(zhuǎn)是由于無質(zhì)量流羽流的卷吸作用。(3)射流失效是由于熱源的次生輻射作用,減弱了送風(fēng)射流動量,從而不能完全覆蓋工作區(qū),并給出了送風(fēng)射流失效的條件Ard0.23�；谘芯拷Y(jié)果,指出了對工作區(qū)優(yōu)化控制的方向。其次,人體會對混合對流流場產(chǎn)生重要影響。人體的存在使得送風(fēng)射流發(fā)生偏轉(zhuǎn)、熱源羽流貼附人體,造成人體局部微環(huán)境流動特性與熱特性的劇烈變化,基于數(shù)值模擬的方法研究了送風(fēng)射流速度、溫度,熱源強度、尺寸,背景溫度對人體熱特性及熱源特性的影響。最后,基于研究結(jié)果,采用數(shù)值模擬的方法對工作區(qū)控制的優(yōu)化方向進行了驗證。通過降低屋頂溫度,可降低次生輻射對送風(fēng)射流的影響,進而增大送風(fēng)射流的有效性。通過研究得出自地面至0.45m處人體表面輻射最大,因此在熱源與人體之間增設(shè)0.45m高的防輻射隔熱板,可有效減小熱源對人體表面的輻射得熱量,并研究了降低輻射板溫度對人體熱特性的影響。
[Abstract]:With the rapid development of economy, indoor pollution of industrial buildings is becoming more and more serious. All kinds of harmful substances and residual heat and moisture in the industrial production process make the working environment of workers very bad and seriously endanger the health of operators. Local air supply is a kind of energy saving ventilation method. For large industrial buildings with fixed operation position, it is especially suitable to use local air supply mode to control the workers' working area, which can effectively improve the local micro-environment of the working area and reduce the energy consumption. In industrial buildings, there are often high intensity heat sources. The natural convection caused by heat sources, the characteristics of human heat plume and the characteristics of air flow under the coupling of local forced convection are not clear. The application of local air supply system in industrial buildings is limited. In order to improve the performance of local air supply system and reduce energy consumption, the flow mechanism of mixed convection, the flow characteristics and thermal characteristics of mixed convection need to be deeply studied and discussed. In this paper, the local microenvironment control of the working area with high temperature heat source is studied. Firstly, the mixed convective flow of the air jet and the surface plume is studied. The effects of jet velocity, air temperature, heat source intensity, heat source size and background temperature on the mixed flow field were studied by means of experiments and numerical simulation. The characteristics of mixed convection flow are found: the "exclusion" of jet and plume, that is, the mutual exclusion of jet and plume, the deflection of jet to the direction of feather flow, and the failure of jet (which can not cover the working area) under the action of high intensity plume. The corresponding flow mechanism is revealed as follows: (1) when the jet is weak, the velocity decreases and the pressure increases in the interaction zone, while on the other side of the jet and plume, the velocity increases and the pressure decreases due to entrainment. Thus, the pressure difference that leads to the repulsive flow is produced. When the jet is strong, the jet impinges on the ground and the ejection momentum turns to push the plume. (2) the jet deflects toward the feather stream because of the entrainment of the mass flow plume. (3) the jet failure is caused by the secondary radiation of the heat source. The flow momentum of the supply air jet is weakened, so that the working area can not be completely covered, and the condition of the failure of the supply air jet Ard0.23. is given. Based on the research results, the direction of optimal control of the working area is pointed out. Secondly, the human body will have an important effect on the mixed convection flow field. The existence of human body causes the air jet to deflect and the heat source plume to attach to the human body, resulting in drastic changes in the flow characteristics and thermal characteristics of the local microenvironment of human body. Based on the numerical simulation method, the velocity, temperature, and heat source intensity of the air jet are studied. The effect of the size and background temperature on the thermal characteristics and heat source characteristics of the human body. Finally, based on the research results, the optimization direction of the work area control is verified by numerical simulation. By reducing the roof temperature, the influence of secondary radiation on the air jet can be reduced, and the effectiveness of the air jet can be increased. From the ground to 0.45m, the maximum radiation of human body surface is obtained. Therefore, the addition of 0.45m high anti-radiation insulation board between the heat source and the human body can effectively reduce the radiation from the heat source to the human body surface. The effect of reducing the radiation plate temperature on the thermal characteristics of human body is also studied.
【學(xué)位授予單位】：西安建筑科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TU83

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