| 1. |
- Moreau, V., et al.
(författare)
-
Pool CFD modelling : lessons from the SESAME project
- 2019
-
Ingår i: Nuclear Engineering and Design. - : ELSEVIER SCIENCE SA. - 0029-5493 .- 1872-759X. ; 355
-
Tidskriftsartikel (refereegranskat)abstract
- The current paper describes the Computational Fluid-Dynamics (CFD) modelling of Heavy Liquid Metal (HLM) flows in a pool configuration and in particular how this is approached within the Horizon 2020 SESAME project. SESAME's work package structure, based on a systematic approach of redundancy and diversification, is explained along with its motivation. The main achievements obtained and the main lessons learned during the project are illustrated. The paper focuses on the strong coupling between the experimental activities and CFD simulations performed within the SESAME project. Two different HLM fluids are investigated: pure lead and Lead-Bismuth Eutectic. The objective is to make CFD a valid instrument used during the design of safe and innovative Gen-IV nuclear plants. Some effort has also been devoted to Proper Orthogonal Decomposition with Galerkin projection modelling (POD-Galerkin), a reduced order model suited for Uncertainty Quantification that operates by post-processing CFD results. Assessment of Uncertainty highly improves the reliability of CFD simulations. Dedicated experimental campaigns on heavily instrumented facilities have been conceived with the specific objective to build a series of datasets suited for the calibration and validation of the CFD modelling. In pool configuration, the attention is focused on the balance between conductive and convective heat transfer phenomena, on transient test-cases representative of incidental scenarios and on the possible occurrence of solidification phenomena. Four test sections have been selected to generate the datasets: (i) the CIRCE facility from ENEA, (ii) the TALL-3D pool test section from KTH, (iii) the TALL-3D Solidification Test Section (STS) from KTH and (iv) the SESAME Stand facility from CVR. While CIRCE and TALL-3D were existing facilities, the STS and SESAME Stand facility have been conceived, built and operated within the project, heavily relying on the use of CFD support. Care has been taken to ensure that almost all tasks were performed by at least two partners. Specific examples are given on how this strategy has allowed to uncover flaws and overcome pitfalls. Furthermore, an overview of the performed work and the achieved results is presented, as well as remaining or new uncovered issues. Finally, the paper is concluded with a description of one of the main goals of the SESAME project: the construction of the Gen-IV ALFRED CFD model and an investigation of its general circulation.
|
|
| 2. |
- Fischer, Andreas, et al.
(författare)
-
A 2-propanol solvate of (RS)-phenylsuccinic acid
- 2004
-
Ingår i: Acta Crystallographica Section E. - : International Union of Crystallography (IUCr). - 1600-5368. ; 60, s. O979-O981
-
Tidskriftsartikel (refereegranskat)abstract
- A solvate of (RS)-phenylsuccinic acid (RS-PSA) has been obtained from 2-propanol ( IPA). The compound, C10H10O4.C3H8O, crystallizes in the monoclinic crystal system (space group C2/c). It features molecules of the S form of the acid, one of whose carboxy groups is connected to one carboxy group of a molecule of the opposite chirality via two hydrogen bonds. The second carboxy group of the S molecule is connected to two other S molecules via the OH groups of two 2-propanol solvent molecules.
|
|
| 3. |
- Fischer, Andreas, et al.
(författare)
-
A metastable modification of (RS)-mandelic acid
- 2003
-
Ingår i: Acta Crystallographica Section E. - : International Union of Crystallography (IUCr). - 1600-5368. ; 59, s. O1113-O1116
-
Tidskriftsartikel (refereegranskat)abstract
- A metastable modification of (RS)-mandelic acid, C8H8O3, was obtained from an aqueous solution. The structure features hydrogen-bonded double chains of acid molecules, which run along the a axis of the crystal. The structure shows a close relationship to that of the pure enantiomer and differs significantly from the structure of the stable modification of the racemate. There are two molecules in the asymmetric unit.
|
|
| 4. |
- Fischer, Andreas, et al.
(författare)
-
(RS)-Phenylsuccinic acid
- 2003
-
Ingår i: Acta Crystallographica Section E. - : International Union of Crystallography (IUCr). - 1600-5368. ; 59, s. O485-O487
-
Tidskriftsartikel (refereegranskat)
|
|
| 5. |
- Fischer, Andreas, et al.
(författare)
-
(S)-Phenylsuccinic acid
- 2003
-
Ingår i: Acta Crystallographica Section E. - : International Union of Crystallography (IUCr). - 1600-5368. ; 59, s. O319-O320
-
Tidskriftsartikel (refereegranskat)abstract
- (S)-Phenylsuccinic acid, C10H10O4, crystallizes from water with two molecules per asymmetric unit. In the crystal structure, the carboxyl groups of each acid molecule are connected to those of adjacent molecules via hydrogen bonds; each molecule is connected to three other molecules, forming infinite chains.
|
|
| 6. |
- Profir, V. M., et al.
(författare)
-
Crystallization of stable and metastable phases of phenylsuccinic acid
- 2006
-
Ingår i: Crystal Growth & Design. - : American Chemical Society (ACS). - 1528-7483 .- 1528-7505. ; 6:5, s. 1143-1153
-
Tidskriftsartikel (refereegranskat)abstract
- In the crystallization of a racemic mixture, formation of a conglomerate, i.e., a mechanical Mixture of enantiomerically pure crystals, is the basic requirement for separation of enantiomers by preferential crystallization. Phenylsuccinic acid (PSA) is in the literature reported as a system forming a racemic compound, i.e., each crystal is an ordered mixture of the two enantiomers. In the present work, the properties of PSA were explored, with the underlying ambition of finding a conglomerate. Racemic PSA was crystallized by unseeded batch cooling crystallization in water, in acetic acid, and in 2-propanol (IPA). The corresponding data on solubility and the metastable limits were determined. Crystallization of racemic PSA in seven different solvents generated racemic PSA solvates with 2-propanol and with dioxane, respectively. The solubility of the (RS)-PSA.IPA solvate was determined, and the transition temperature between the solvated and the ansolvate (RS)-PSA I was found to be 16.5 degrees C. In addition to the solution crystallization investigation, an extensive thermal analysis of the racemate and of pure (S)-PSA was performed. A metastable racemate was produced by melt crystallization but was never obtained in Solution crystallization, although unusually high cooling rates combined with different levels of concentration and stirring conditions were used. Throughout this work, the solution concentration and the crystal modification type obtained upon nucleation were determined by in situ ATR-FTIR spectroscopy coupled with multivariate Partial Lease Squares (PLS) calibrations. The work suggests that for a system reported to be forming a racemic compound, there are at least three opportunities to find a conglomerate that should be explored: (i) a conglomerate that may be the stable modification at a different higher or lower temperature; (ii) a metastable conglomerate that may have a sufficient stability for a separation to be performed; (iii) a solvated conglomerate, either more or less stable than the ansolvate.
|
|
| 7. |
- Profir, Veronica M., et al.
(författare)
-
Influence of solvent and the operating conditions on the crystallization of racemic mandelic acid
- 2004
-
Ingår i: Crystal Growth & Design. - : American Chemical Society (ACS). - 1528-7483 .- 1528-7505. ; 4:2, s. 315-323
-
Tidskriftsartikel (refereegranskat)abstract
- The crystallization of racemic mandelic acid is studied in unseeded batch cooling experiments in four solvent systems. Apart from the thermodynamically stable racemic compound, a metastable modification of the racemic compound is also found to initially form upon nucleation. The metastable racemate is characterized by thermal analysis (MDSC), FTIR spectroscopy, and X-ray powder diffraction (XRPD). The experiments show that the type of crystal modification that is formed upon nucleation is strongly influenced by the operating conditions such as filtration, cooling rate, and stirring rate, as well as by the solvent. The solvent effect can be related to the characteristics of the crystal structures of the two modifications, and to the hydrogen bonding properties of the solvent. The crystal structure of the metastable modification of the racemic compound is very similar to that of the pure enantiomer, which explains the similarity of the FTIR spectra, the XRPD diffraction pattern, and the thermodynamic stability.
|
|
| 8. |
- Profir, V. M., et al.
(författare)
-
Study of the crystallization of mandelic acid in water using in situ ATR-IR spectroscopy
- 2002
-
Ingår i: Crystal Growth & Design. - : American Chemical Society (ACS). - 1528-7483 .- 1528-7505. ; 2:4, s. 273-279
-
Tidskriftsartikel (refereegranskat)abstract
- Different aspects related to the separation of enantiomers of mandelic acid by direct crystallization are explored. Solubility, nucleation, and solid-phase transformation in aqueous solutions are investigated. Results show that a metastable conglomerate can be formed for a substance known to appear as a racemic compound. After a time-lag, the conglomerate transforms into the stable racemic compound. The time-lag ranges from a few minutes to 8 h depending on the operation conditions. The time-lag decrease's at increasing concentration/temperature and in the presence of micrometer-sized particles. In situ attenuated total reflectance infrared (ATR-IR) spectroscopy and a partial least squares (PLS) calibration model are used to record the concentration of dissolved mandelic acid. Since no sampling is required and the calibration set, which is used on both racemic and enantiomerically pure solutions, can be built using the cheaper racemate, the technique should be of particular interest in applications involving chiral substances.
|
|
