Heat Leakage Of Medium And Large Vertical Cylinder Cryogenic Tanks

Storage tanks for cryogenic liquids are widely used in energy,environmental protection,chemical,pharmaceutical and food industries[1].Due to the low manufacturing cost and difficult construction of the vertical cylinder cryogenic tank,the large and medium-sized vertical cylinder cryogenic tank still occupies the main market of cryogenic storage tank[2].As the main index to measure the economic type of the storage tank,the leakage heat of the low temperature storage tank is naturally concerned by the users.How to calculate the leakage heat of the vertical cylinder tank accurately and quickly has important engineering value for the design,manufacture and maintenance of the tank.At this stage,the methods to calculate the heat leakage of cryogenic tank are:experimental method,computational method and numerical simulation method.In this paper,an analytical solution for the leakage heat at the corner of a vertical cylinder cryogenic storage tank is derived for the first time,and it is applied to a vertical cylinder cryogenic storage tank of a company.The calculation formula method and numerical simulation method in this paper,give out a method to calculate the heat leakage of cryogenic liquid storage tank is close to the real heat leakage of.It has high engineering application value.The main contents of this paper include the following points:1.According to the heat transfer theory,three heat transfer models of vertical cylinder cryogenic tank are given,and the heat transfer formula of each heat transfer model under different boundary conditions is deduced;the three type heat transfer model for calculating the analytical solution and the finite element numerical simulation solution for comparison.Find the analytical solution and the numerical simulation solution of the kiss was better,and the mesh sensitivity of three kinds of heat transfer model.2.In order to obtain the analytical solution of heat leakage at the corner of a large vertical cylinder cryogenic tank.Based on the theory introduced in the second chapter,a two-dimensional axisymmetric heat conduction model in a steady state is established.Then,the analytic solution of the temperature field at the corner of the middle and large vertical cylinder cryogenic tank is derived by using the separation variable method,the variable replacement method and the superposition principle.The obtained analytical solution agrees well with the numerical simulation solution of the finite element software ANSYS.3.In order to get a simple calculation can be directly applied in practical engineering,the superposition of analytical solutions for the foundation,adopt the method of separation of variables is reasonable,related to the geometric parameters,relates to a cryogenic storage tank corner model physical parameters and load parameters are extracted,and finally fitting a simple convenient calculation.Simple and numerical solutions have higher kiss.4.In order to understand the influence of anchorage belt on heat leakage,temperature distribution,heat flux density and temperature gradient of cryogenic storage tank.A three dimensional finite element model with an anchorage zone is established,and the loading boundary condition of the model is compared with that of the model without anchorage zone.In the case of given anchorage zone,the influence of the thermal conductivity of the anchorage zone on the heat leakage,the temperature field and the heat flux distribution of the cryogenic storage tank is studied.5.In order to obtain a method for estimating the total heat leakage of a large vertical cylinder cryogenic storage tank.The calculated values obtained by this formula are compared with the numerical values,and the corresponding formulas are further revised.Finally,a formula with higher kiss is obtained.6.According to the domestic and international standards,the judgment of whether the vertical cylinder cryogenic tank should be installed is given.For the storage tank at the corner of the stress level,the relationship and anchorage zone were further research.The results showed that:no anchorage zone can not only reduce the storage tank leakage of heat,but also can reduce the overall stress level of the tank.When the cryogenic tank is designed,if the tank itself can meet the seismic conditions,it is recommended to adopt the design of the non anchorage tank.Based on the large vertical cylindrical storage tank of low temperature heat leakage of theoretical analysis and numerical simulation research,found a large vertical cylindrical cryogenic tanks close to the real heat leakage estimation method and simple calculation,provides a theoretical and technical support for the corresponding calculation of cryogenic tank heat leakage.