Construction of Thermodynamic Properties Look-Up Table with Block-Structured Adaptive Mesh Refinement Method

Abstract

An efficient procedure for evaluating the thermodynamic and transport properties of real fluids was presented. Block-structured adaptive mesh refinement was used to construct the equations of state look-up table, which provides uniform accuracy over a selected thermodynamic plane with fewer grids. An overlapping uniform index domain was developed to provide fast search capability. Properties can be evaluated by bilinear, bicubic, and biquintic interpolation to achieve different levels of function continuity and thermodynamic consistency. Reconstruction discontinuity may appear across the interface of unequally sized blocks, but the level of discontinuity decreases when reconstruction is based on structured grids on each block. The effectiveness and efficiency of the method was demonstrated by comparing the storage, data retrieval, and computational fluid dynamics samples. The storage requirement decreases by 20 to 80% compared to the table constructed with uniform mesh. The overlapping uniform index domain is 14 to 19% faster than the tree data-structure in computational fluid dynamics calculations with the table of 0.1% accuracy. When reconstructed property is within 0.1% of the exact value, the degree of discontinuity is small enough to obtain a convergent solution in computational fluid dynamics cases. An equation of state table look-up method is as efficient as ideal gas equations of state and two orders of magnitude faster than the complex thermodynamic database.