便携式旋转粘度计校准恒温容器的温度响应特性研究

Research on temperature response characteristics of portable thermostatic bath to rotational viscometer calibration

对不同结构及流动参数下,一种加装螺旋隔板的便携式旋转粘度计校准恒温容器内流动与传热进行了数值模拟。考察了旋转粘度计内液体的温度响应特性。模拟采用SIMPLE算法求解压力与速度的耦合,对求解变量采用QUICK格式离散,湍流模型采用Realizable k-ε模型。模拟结果表明:当水套内螺旋导流隔板圈数增加,与加热情况相比,冷却时内杯流体温度分层现象增强,不利于满足被测粘度液温度均匀性要求;加热和冷却温差相同时,对于加装不同层数螺旋隔板的结构,加热时的温度响应基本相同为0.24℃/min,冷却时温度响应随着螺旋隔板圈数增多而降低,最多相差0.036℃/min;当循环水量一定,恒温容器温度响应随热流密度提高而加快,但仅改变循环水量,对不同结构恒温容器的温度响应影响并不明显。

The numerical simulation of the flow and heat transfer in a portable thermostatic bath with spiral baffles to rotational viscometer calibration under different flow and structure parameters is developed.The temperature response characteristics of fluid in the rotational viscometer are investigated.SIMPLE algorithm is used to solve the pressurevelocity coupled governing equations employing QUICK-type scheme for variables discretization.Realizable k-Epsilon Model is adopted for modelling turbulence.The numerical results show that when the number of spiral baffles in the water jacket increases,compared with the heating condition,Thermal stratification phenomena of fluid within the cup in cooling condition is enhanced,which is not conducive to meet the temperature uniformity requirements for viscosity liquid which to be measured.When the temperature difference between heating and cooling condition is same,for Installed different spiral baffles structure heating temperature response is basically the same as 0.24℃/min.Cooling temperature response decrease with the increasing number of spiral baffles,and the maximum difference is 0.036 ℃/min.With a fixed flow rate,temperature response of thermostatic bath increases with the increase of heat flux density.While just change flow rate,the temperature response of thermostatic bath with different structure is not obvious.