偏心环空通道内强迫对流换热实验研究

发布时间：2019-05-19 07:28

【摘要】：注蒸汽开采稠油时通过井筒将蒸汽注入油层,在此过程中蒸汽通过同心油套环空与地层之间发生热量交换。但由于钻井过程井眼轨迹并非直线,而是螺旋线形,导致井筒油套环空出现偏心,而偏心环空中的换热特性研究还不充分,且目前还没有成熟的计算方法,因此准确计算偏心环空换热过程至关重要。本文以薄壁不锈钢环形套管为研究对象,以水为介质,针对三种不同管径比(3.06、2.25、1.875)、三种不同偏心度(0.2、0.5、0.8)及不同雷诺数,在内管恒定入口温度及流量,环空恒定入口温度,外管外壁面与空气自然对流的条件下对竖直偏心环空通道内的流动与换热特性进行实验,并对环空通道内换热特性的影响因素进行分析,得到环空通道内单相强迫对流换热的实验关联式。同时通过数值模拟与实验结果相对比,得到了以下结论:偏心度对换热的影响在不同管径比下呈现出不同的规律。在管径比为3.06时,偏心度的增大总是强化换热。在管径比为1.875时,偏心度对换热的影响随着雷诺数的不同分为两个区域:当Re2000时,偏心度的增大会削弱环空通道中的对流传热,当Re2000时,呈现出相反的规律,即偏心度的增大会强化环空通道的对流换热。管径比的增大会强化环空通道的换热。但管径比对环空通道换热特性的影响受到偏心度及雷诺数的共同影响。随着偏心度的减小,管径比的增大对换热的强化作用在减弱,随着雷诺数增大,管径比的增大对环空通道内换热的强化作用增强。
[Abstract]:Steam is injected into the reservoir through wellbore when heavy oil is produced by steam injection, in which heat exchange occurs between steam and formation through concentric oil sleeve annulus. However, due to the fact that the wellbore trajectory is not a straight line, but a spiral, resulting in eccentricity in the annulus of the wellbore oil sleeve, the research on the heat transfer characteristics in the eccentric annulus is not sufficient, and there is no mature calculation method at present. Therefore, it is very important to calculate the heat transfer process of eccentric annulus accurately. In this paper, thin-wall stainless steel annular casing is taken as the research object, and water is used as the medium for three different pipe diameter ratios (3.06, 2.25, 1.875), three different eccentricity (0.2, 0.5, 0.8) and different Reynolds numbers. The flow and heat transfer characteristics in a vertical eccentric annular channel are tested under the conditions of constant inlet temperature and flow rate in the inner tube, constant inlet temperature in the annulus, and natural convection between the outer wall of the outer tube and the air. The influencing factors of heat transfer characteristics in annular channel are analyzed, and the experimental correlation of single-phase forced convective heat transfer in annular channel is obtained. At the same time, by comparing the numerical simulation with the experimental results, the following conclusions are obtained: the effect of eccentricity on heat transfer shows different laws under different pipe diameter ratios. When the ratio of pipe to diameter is 3.06, the increase of eccentricity is always enhanced heat transfer. When the ratio of pipe to diameter is 1.875, the effect of eccentricity on heat transfer is divided into two regions with the difference of Reynolds number: when Re2000, the increase of eccentricity weakens the convective heat transfer in annular channel, and when Re2000, it shows the opposite law. That is, the increase of eccentricity will enhance the convective heat transfer of annular channel. The increase of pipe diameter ratio will enhance the heat transfer of annular channel. However, the influence of pipe diameter ratio on the heat transfer characteristics of annular channel is affected by eccentricity and Reynolds number. With the decrease of eccentricity, the enhancement effect of pipe diameter ratio on heat transfer is weakened, and with the increase of Reynolds number, the enhancement effect of pipe diameter ratio on heat transfer in annular channel is enhanced.
【学位授予单位】：中国石油大学(华东)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE357.44;TK124

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