共查询到15条相似文献,搜索用时 109 毫秒
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竖直管外降膜吸收传热传质过程强化的研究 总被引:9,自引:0,他引:9
对LiBr溶液在光滑管和四种换热强化管竖直管外降膜吸收过程进行了实验研究,得到了实验条件下的最佳管型,分析了非绝热吸收过程中传热传质相互作用,相互影响的关系,建立了竖直管外降膜吸收热-质传递过程的数学模型,并对该过程进行了数值计算,模型计算值与实验结果的比较证明该模型具有较好的适用性。 相似文献
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热管式降膜吸收器的传热传质 总被引:7,自引:0,他引:7
对热管式降膜吸收顺溶液吸收传热传质并通过热管移出吸收热的过程进行了数值研究,根据所建立的数学模型,通过求解热管加热段外壁面溶液波动降膜的动态二维偏微分方程和热管传热方程,研究了膜雷诺数,低位余热温度,输出温度等因素对传热管质过程的影响,对进一步工作提出了新的见解。 相似文献
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吸收式热泵系统的计算和强化 总被引:1,自引:0,他引:1
《纯碱工业》1986,(2)
本文通过试验,研究了溴化锂吸收热泵系统中的主要设备——降膜吸收器的传质、传热过程,并提出了对具有传递阻力的热泵系统中,特性系数的计算方法.根据试验数据计算出的结果表明:在降膜吸收器中用螺纹管代替普通的光滑管,可以大大提高系统的有效温升和特性系数. 相似文献
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分别考察了在垂直螺旋管内降膜式第2类吸收热泵系统中,溶液流量、循环热水流量、操作温度对吸收器传热传质系数、系统性能系数COP及热效率Eth的影响。实验结果表明:随着溶液流量的增加,吸收器的传热传质系数也逐渐增大,而COP与Eth则有下降趋势;增加循环热水流量,吸收器传热传质系数也增大,但对COP与Eth的影响却较小;对于操作温度,吸收器传热传质系数会随着废热温度的升高而增大,随着冷却水温度的降低而增大。同时,通过软件ABSIM的模拟计算,得到的数据与实验数据吻合较好。 相似文献
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提出了一种双面液膜反转方案,竖直布置2组或2组以上交叉双尺度波纹板束为传热面,在上板束各对板底部设置耙形导流器,交叉地将上板束各对板两侧的液膜引至下板束异侧,然后利用液膜与具有水平沟槽的波纹板片上的表面张力作用使反转后的下降液膜均匀化,以此实现液膜反转和交叉双尺度波纹板技术的复合强化。建立了溴化锂水溶液在2段光滑平板上降膜反转吸收过程的传热传质数学模型并进行了数值计算。给出了反转液膜前后液膜内流场、温度场、质量分数分布计算结果,并讨论了溴化锂水溶液降膜吸收传热和传质过程中反转次数对传热和传质系数的影响。 相似文献
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研究了透过致密无孔膜的传热传质过程,考察了传热传质的相互作用,建立了膜过程中热质耦合传递的数学模型,并以湿空气透过薄膜分离过程为例,分析了温差及浓度差的变化对传热传质过程的影响,发现温差及浓度差的变化会引起热阻及湿阻的变化,从而进一步影响热流量和传质通量,所以对传热传质过程有加成作用。 相似文献
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根据船用条件下吸收器内溶液降膜吸收的特点,建立了摇摆状态下垂直管内TFE(2,2,2-trifluoroethanol,三氟乙醇)/NMP(N-methyl-2-pyrrolidone,甲基吡咯烷酮)降膜吸收过程中动量、热量和质量传递的物理和数学模型.模型中充分考虑了转动附加惯性力对降膜流场中液膜厚度、速度、温度和浓度分布的影响.采用膜内积分与全隐式有限容积相结合的数值方法求解理论模型.通过对计算结果的分析发现,在摇摆状态下TFE/NMP降膜吸收过程中,转动附加惯性力的存在使得速度和温度等状态参数的分布具有一定周期性和对称性. 相似文献
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Experimental measurements for the heat and mass transfer in laminar wavy film absorption with the presence of non-absorbables are presented. Water vapor was absorbed into a falling film of aqueous lithium chloride solution on a vertical tube with the air present in the gas phase acting as the non-absorbable whose concentration was accurately detected by a mass spectrometer gas analyzer. Although the depressing effect of the air on the absorption rate was much more significant in the low air concentration range, the absorption reduction rate with increasing air concentration was found to be lower than that reported previously. The reduction was found to be continuous even up to 30% of air content. Besides the non-absorbables, the effects of other operational parameters such as solution flow rate, inlet solution temperature, inlet solution concentration, absorber wall temperature, absorber water vapor pressure, and effective contact length on the absorption rate were also tested. These effects were shown to follow trends similar to those predicted by a numerical solution for smooth film absorption. The heat and mass transfer coefficients were correlated by using Reynolds number, Prandtl number, Schmidt number, capillary-buoyancy coefficient and air concentration. 相似文献
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The problem of appropriate boundary conditions for mass transfer within the liquid film in chemical absorption ih reconsidered. It has been shown that the most general solution to the problem of mass transfer in the liquid film can be obtained if a fixed bulk composition is taken as a film-bulk boundary condition to the differential balance equations of the film. This method leads to solutions which can be incorporated into absorber balance equations of any type. As an illustrative example, the simultaneous absorption of two gases which react together in a semi-batch absorber is discussed. A new, approximate but very simple and accurate solution to this problem is proposed. 相似文献
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The influence of two alcoholic surfactants on the flow patterns of falling film tube bundles is investigated. The flow patterns are measured in a single-stage absorption chiller in the absence of surfactants. The surface tension of H2O/aqueous LiBr solution with different concentrations of 1-octanol and 2-ethylhexanol is measured at low pressure in a saturated atmosphere. Small quantities of surfactants in the aqueous solution do not have an influence on the flow patterns of the condenser and evaporator, while a shift from droplet to jet mode is predicted in the absorber and generator at the typical working condition of an absorption chiller. 相似文献