共查询到17条相似文献,搜索用时 46 毫秒
1.
矩形截面气升式环流反应器中非牛顿流体的气含率与传质系数的研究 总被引:1,自引:0,他引:1
研究了一种矩形截面气升式环流反应器,用幂律τ=η_ογ~n(n<1)来表示流体流变学特性的变化.在这类反应器中,假塑性非牛顿流体的气含率ε_g与传质系数K_La的变化规律可用半经验关联式表示ε_g=0.2535(η_ο5000~(n-1))~(-0.161)(1+A_d/A_r)~(-0.434)u_(gr)~(0.856-0.161n)K_La=0.0192(η_ο5000~(n-1))~(-0.902)(1+A_d/A_r)~(-1.228)u_(gr)~(1.955-0.902n)并讨论了该类反应器结构及运行状况,流体性质变化时,反应器传质动力学特性、流动特性和操作弹性变化的规律. 相似文献
2.
气升式外环流反应器的体积传质系数 总被引:1,自引:0,他引:1
以Higbie的渗透理论和Kolmogoroff的湍流理论为基础,提出了计算液体旋涡在气液相界面暴露时间的方法,并建立了预测体积传质系数的模型方程。在不同管径比下的外环流反应器中,对空气 水体系测定了操作气速对体积传质系数、循环液速和气含率的影响。将体积传质系数与表观气速和下降管与上升管的面积比按幂函数进行关联,其预测值和试验值符合较好。 相似文献
3.
气升式外循环淤浆反应器的气含率和传质的研究 总被引:4,自引:1,他引:4
在气升式外循环环流反应器中,对空气-水两相系统的气含率■_(go)和气-液氧体积传质系数进行了研究,获得关联式:■_(go)=1.384(u_G/(u_G+u'_L)~(0.34)u_G~(0.71)k_Lα=0.0463(u_G/(u_G+u'_L)~(0.24)u_G~(0.52)对空气-水-α-氧化铝三相淤浆系统,采用丝网过滤将催化剂留于反应器上升管中。此时,上升管中气含率■_(go)和传质系 k_La可用下面公式来计算:■=1.384/(1+0.504■_s~(0.13))(u_G/(u_G+u'_L))~(0.34)u_G~(0.71) (■_s=0.001~0.05)■ 相似文献
4.
5.
6.
鼓泡塔中非牛顿流体体系气含率的研究 总被引:4,自引:0,他引:4
本文是在直径为0.1m、高为1m的鼓泡塔中,选用水、Na_2SO_3/CMC溶液,CMC溶液作为介质,采用单孔喷嘴布气,孔径为0.01m,测定了鼓泡塔的气含率,对实验数据进行了关联,提出了气含率的关联式,并与文献中有关结果进行了比较。 相似文献
7.
以非牛顿型流体在气升式内环流反应器中流动特性为研究对象,考察了在气-液-固三相体系中气含率和液体循环速度随不同的表观气速、固体颗粒粒径和浓度、设备结构尺寸的变化规律。对实验数据进行了回归处理得到气含率和循环速度的经验关联式,并对非牛顿型流体和牛顿型流体在同一反应器中的流动特性作了比较 相似文献
8.
针对矩形卧式多级串联环流反应器,在改变结构和气速的情况下,对全系统的气含率、上流区和下流区的气含率、液相循环速度、液相返混等进行了实验考察,并利用漂流模型,最小能耗原理等进行了模拟计算。 相似文献
9.
10.
11.
在为微生物高密度培养而设计的10L多段内导流筒气升式生物反应器中,研究了Na2SO3-空气体系单孔喷嘴和烧结金属管等不同气体分布器对气含率ε、体积氧传质系数KLa和流动特性的影响.结果表明,孔径为20~25μm的烧结金属管的整体性能最好,在最佳操作气速3.7~4.0cm/s下,ε超过19%,KLa可达0.29s-1.其ε和KLa随Ug有如变化规律:ε=0.1952-1.53510-2e-1.391UgKLa=0.27+2.9710-2Ug-7.2310-3U2g(1.5<Ug<6cm/s 相似文献
12.
13.
Heat transfer in five air-lift and bubble column bioreactors has been investigated. Water (Newtonian) and xanthan solutions (non-Newtonian) were used. The effects of superficial gas velocity, liquid-phase viscosity and riser-to-downcomer cross-section area ratio have been studied. In air-lift slightly higher heat transfer coefficients were observed than in bubble column reactors. The superficial gas velocity and the effective liquid-phase viscosity influence strongly the heat transfer performance in all systems studied. Following the surface renewal concept, general correlations for heat transfer in Newtonian and non-Newtonian fermentation broth were developed. They describe precisely heat transfer coefficients in a wide range of operating and geometrical conditions. 相似文献
14.
通过实验研究,得到了非牛顿型浆液鼓泡塔内压力的轴向分布关联式,进而得到了塔内气含率的轴向分布式。为进一步研究非牛顿型浆液鼓泡塔流体力学行为打下基础。 相似文献
15.
16.
17.
In an internal loop airlift reactor of 55L working volume,the gas-liquid volumetric oxygenmass transfer coefficient k_Lα,gas holdup ε_G and liquid circulation time t_c were measured with the sol-ution of carboxymethyl cellulose(CMC)to simulate the performance of a reactor with highly viscousbroth.Electric conductivity and oxygen probes were used to measure the local gas holdup,liquidcirculation time and oxygen mass transfer coefficient in the individual sections of the reactor(riser,downcomer and the gas-liquid separating section at the top of the reactor)and the total reactor,respectively.The values of k_Lα for the riser,downcomer and separation sections of the reactor were alsoestimated and compared with that for the total reactor.The results show that,both k_Lα and ε_G in-crease but t_c decreases with increasing gas velocity.Correlations and comparisons with works reportedin the literature are also presented.Data show that the methods developed for k_Lα measurements inthe individual section and 相似文献