Solids dynamics

Shahinpoor, M., H.S. Lausen, J.L. Wise, J.R. Asay, C.H. Konrad, and R.D. Harday (1985), Ballistics Computer Code Manupulation for Optimal Design and Operation of Two-Stage Light Gas Guns, SNL—Solid Dynamics Department, Quarterly Report, October 1985. 

L.M. Taylor and D.P. Flanagan, PRONTO 2D A Two-Dimensional Transient Solid Dynamics Program, SAND86-0594, Sandia National Laboratories, Albuquerque, NM, 87185, 1987. 

In the solid, dynamics occurring within the kHz frequency scale can be examined by line-shape analysis of 2H or 13C (or 15N) NMR spectra by respective quadrupolar and CSA interactions, isotropic peaks16,59-62 or dipolar couplings based on dipolar chemical shift correlation experiments.63-65 In the former, tyrosine or phenylalanine dynamics of Leu-enkephalin are examined at frequencies of 103-104 Hz by 2H NMR of deuterated samples and at 1.3 x 102 Hz by 13C CPMAS, respectively.60-62 In the latter, dipolar interactions between the 1H-1H and 1H-13C (or 3H-15N) pairs are determined by a 2D-MAS SLF technique such as wide-line separation (WISE)63 and dipolar chemical shift separation (DIP-SHIFT)64,65 or Lee-Goldburg CP (LGCP) NMR,66 respectively. In the WISE experiment, the XH wide-line spectrum of the blend polymers consists of a rather featureless superposition of components with different dipolar widths which can be separated in the second frequency dimension and related to structural units according to their 13C chemical shifts.63... 

Appendix B consists of a systematic classification and review of conceptual models (physical models) in the context of PBC technology and the three-step model. The overall aim is to present a systematic overview of the complex and the interdisciplinary physical models in the field of PBC. A second objective is to point out the practicability of developing an all-round bed model or CFSD (computational fluid-solid dynamics) code that can simulate thermochemical conversion process of an arbitrary conversion system. The idea of a CFSD code is analogue to the user-friendly CFD (computational fluid dynamics) codes on the market, which are very all-round and successful in simulating different kinds of fluid mechanic processes. A third objective of this appendix is to present interesting research topics in the field of packed-bed combustion in general and thermochemical conversion of biofuels in particular. 

The combustion system and the boiler system of a PBC system, according to the three-step model, can be modelled by means of CFD codes [4,5]. However, an allround bed model [6,7] to simulate the thermochemical conversion of the solid fuel inside the conversion system does not yet exist. Bed models of the conversion system will herein also be referred to as CFSD code computational fluid-solid dynamics), analogue to the CFD code. From the three-step model point of view, it is clear that without a CFSD code simulating the thermochemical conversion of the packed bed in the conversion system, simulation of the whole PBC system can never be completely successful. 

The solid phase of a batch bed can either be fixed, moving or mixed, whereas continuous fuel beds can either be moving or mixed. A successful and comprehensive mathematical model needs to consider these three modes of fuel-bed movement. There is a close analogy between the fluid-solid dynamics, where we have proposed fixed, moving, and mixed, and the fluid dynamics where the corresponding terminology is stagnancy, laminar flow and turbulent flow, respectively. 

The thermochemical conversion of biofuels takes place in the conversion system and belongs to the science of two-phase phenomena (fluid-solid dynamics), that is, heat and mass transport processes take place inside and between a solid phase and a gas phase. This phenomenology is well illustrated by Balakrishnen and Pei [49], see Figure 40. 

The long-term goal in the science of thermochemical conversion of a solid fuel is to develop comprehensive computer codes, herein referred to as a bed model or CFSD (computational fluid-solid dynamics). Firstly, this CFSD code must be able to simulate basic conversion concepts, with respect to the mode, movement, composition and configuration of the fuel bed. The conversion concept has a great effect on the behaviour of the thermochemical conversion process variables, such as the molecular composition and mass flow of conversion gas. Secondly, the bed model must also consider the fuel-bed structure on both micro- and macro-scale. This classification refers to three structures, namely interstitial gas phase, intraparticle gas phase, and intraparticle solid phase. Commonly, a packed bed is referred to as a two-phase system. 

When experimental NFS spectra of samples with finite thickness are recorded, the time decay also shows modulations attributed to coherent multiple scattering occurring in solids (dynamical beats). These superimposed modulations have different (non-periodic) time modulation and are taken into account when the spectra are fitted. 

Pikal, M.J. Stability of amorphous solids dynamics, reactivity, and the glass transition. Proceedings of BioPharm, Cambridge, MA, 1993. 

Other parameters that may be defined in dynamic shear rheology are the viscous dynamic viscosity, rj = G"/o, and the solid dynamic viscosity, tj" = G Ico. 

A computer-aided particle-tracking facility (CAPTF) has been developed to measure the motion of radioactive tracers in fluidized beds. This achievement was the first successful attempt to use the radioactive tracer technique to obtain detailed quantitative information on solids dynamic data in fluidized beds. The CAPTF makes use of one or more radioactive tracer particles that are dynamically identical to the bed particles under study. In... 

Sun, J. G., 1989, Analysis of Solids Dynamics and Heat Transfer in Fluidized Beds, Ph. D. Thesis, Univ. of Illinois, Urbana-Champaign. 

Energy-momentum algorithms for nonlinear solid dynamics and their assumed strain finite element formulation... 

---