In this MR, several errors for the calculation of the thermal resistance in 1U and 2U type BHE are fixed. The related benchmark "3D 2U BHE" (2U type BHE) and several 1U type BHE benchmarks CTest results are updated accordingly.
Firstly, For 1U and 2U type BHE, a common mistake are found in the correction procedure when facing a negative thermal resistance situation. Details about this problem description can be found in the Section (1.5.5) in FEFLOW White Papers Vol V. In this MR, the previous correction factor 0.66 is fixed to 2/3. And the correction factor 'xi' is fixed in the code for updating its self.
Then, for 2U type BHE, a error regarding the calculation of the pipe thermal resistance is fixed. According to the Eq. (29) in the Diersch's paper (2011) and Eq. (M.1) in the FEFLOW book, the related calculation equation of the thermal resistance in the 2U type BHE seems to be incorrect. This error is fixed in this MR.
After fixing the above errors, the computed pipe thermal resistance from OGS is checked to be the same as the one computed in the FEFLOW software, both for 1U and 2U type BHE.
The 2U BHE benchmark is updated accordingly. For this benchmark, a FEFLOW model is constructed (FEFLOW_BHE_2U_model.zip. And the FEFLOW mesh has been converted into OGS model mesh for the benchmark use (3D_2U_BHE_benchmark.vtu). All the comparison results showed in this benchmark is obtained from these two updated meshes.
The CTest results from the 1U type BHE benchmarks are updated accordingly.
Details changes are list as followed.
fixed the correction procedure for handling the negative thermal resistance problem in 1U and 2U type BHE.
fixed the pipe thermal resistance in the 2U type BHE.
updated the CTest result for 1U and 2U BHE benchmarks.
For 2U BHE benchmark, all the results showed in the documentation between OGS and FEFLOW models are updated according to the FEFLOW fein mesh. Besides, a new comparison is demonstrated for the two models by using the power boundary condition.