A hydrogen depressurization system is required to supply the hydrogen to the fuel cell stack from the storage. In this study, a Tesla-type depressurization construction is proposed. Parallel Tesla-type channels are integrated with the traditional orifice plate structure. A computational fluid dynamics (CFD) model is applied to simulate high-pressure hydrogen flow through the proposed structure, using a commercial software package, ANSYS-Fluent (version 19.2, ANSYS, Inc. Southpointe, Canonsburg, PA, USA). The Peng–Robinson (PR) equation of state (EoS) is incorporated into the CFD model to provide an accurate thermophysical property estimation. The construction is optimized by the parametric analysis. The results show that the pressure reduction performance is improved greatly without a significant increase in size. The flow impeding effect of the Tesla-type orifice structure is primarily responsible for the pressure reduction improvement. To enhance the flow impeding effect, modificat
The hearth status varies accordingly with individual blast furnace (BF) conditions so that the variation of measured hearth refractory temperature is unique. Over the course of a long BF campaign (typically 15–20 years), refractory temperature in the same furnace can also present different trends. This is certainly the case for Whyalla’s No. 2 Blast Furnace (W2BF) as various significant operational events occurred during its 4th campaign starting from 2004. To understand hearth condition throughout the whole W2BF current campaign including refractory, coke bed and liquid flow behaviour, a methodology was proposed to help explain the refractory temperature measurement (trend) based on simplified and comprehensive fluid flow and heat transfer modelling, measured refractory temperatures and other relevant operational data. Results show that through a consistent assessment based on the various sources over the W2BF campaign, a reliable prediction can be made about the current W2BF hear
The fate of plastics entering the 3D ocean circulation from rivers discharge is examined through the Lagrangian analysis of neutrally buoyant particles. Particles are released continuously over 1991-2010 at the surface along the coasts according to monthly estimates of rivers plastic waste input. They are advected by daily currents from a state-of-the-art global ocean model at 1/12° resolution. At the end of the simulation, particles remaining in the surface layer of 1~m thickness represent less than 2\% of the total particles released. These are concentrated in the center of subtropical gyres, mostly in the South Indian Ocean and the North Pacific, in relation with the large sources from Asia, and in good agreement with previous 2D numerical experiments in the surface layer. These patterns remain similar down to about 30 m depth, this upper layer strongly influenced by Ekman currents trapping about 20\% of the total released particles. About 50\% of the total released particles r
This thesis investigates diffusion equations in polar geometries that do not assume azimuthal symmetry. Many of these investigations can be traced back to pioneers like Carswell and Jaeger, but in almost every case the cylindrical or spherical models assume θ independence. Until the work of the Losic Group at University of South Australia was discovered, it was unclear what practical value an investigation of non-axisymmetric mixed boundary problems would have. The cylindrical diatom structure, with its windows open to diffusion, gave the first clear indication that a promising, emergent technology may offer some application.
The introductory chapter attempts to summarize some of the broad array of publications on the subject in the past few years. The burgeoning list of these titles is testimony to the traction that the field of controlled release is currently experiencing. Several important diversions are entered into. These include the importance of the parameter for diffusivity, D