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At present, most multiscale simulation approaches to model the temperature evolution of the molten pool, and the resulting microstructure evolution for selective laser melting, assume an equilibrium freezing range and steady state solidification conditions. This is despite the solidification conditions being observed to be highly unsteady and non-equilibrium. These two assumptions lead to inaccurate predictions of the temperature evolution of the molten pool and thus microstructure predictions. To demonstrate this, an approach to scale-bridging computational models of the laser additive manufacturing process is presented, in which the temperature history is passed from a macroscale molten pool simulation to a microscale phase-field simulation. This linkage is achieved by volume mapping of the temperature field from the grid of the molten pool simulation to the grid of the microstructure simulation. To describe the system evolution at the scale of the molten pool, a computational fluid dynamics (CFD) method that captures the laser–metal interaction, vapour production, gas recoil pressure, fluid flow, surface tension, Marangoni flow, and heat conduction, convection, and radiation is applied. To capture the chemical kinetics of the phase-transition, a non-equilibrium CALPHAD-integrated phase-field (PF) model is applied. The discrepancy between the predictions of the solid front isotherm is quantified as ⩾ 100 K for an Al-10Si alloy under the large observed cooling rate. This leads to a spatial discrepancy in the solidification front between the CFD model, which assumes equilibrium freezing behaviour, and the PF model, which does not, of approximately 10 µm over 50 µs in the present case. Under these conditions, present formulations of multiphase CFD cannot accurately predict the solidification behaviour because of the assumption of equilibrium at the solid–liquid interface. Strategies for reconciling this discrepancy for materials that exhibit rapid solidification under large thermal undercooling will need to be developed for multiscale simulation of additive manufacturing to advance.

Enhanced natural gas recovery (EGR) with supercritical (sc)CO2 sequestration offers the prospect of increased natural gas recovery. High-fidelity reservoir simulations offer a method to quantify the risk of contamination of produced gas by the injected scCO2. Simulations of scCO2 mixing with the reservoir gas have been reported; however the effects of connate water on EGR have not been effectively explored. We extend a prior EGR simulation tool (Patel, May and Johns, 2016; Ref. [1]) to incorporate connate water accounting for its effect on dispersivity and permeability; chemical equilibrium is modelled using a novel, computationally efficient Lagrange multiplier-based approach. The code is applied to a ‘quarter five-spot’ benchmark scenario. The inclusion of connate water generally resulted in a reduction in breakthrough time and a decrease in methane recovery. The connate water's largest effect was to change the scCO2 flow field, which sank towards the reservoir floor, flooded the lowermost accessible layers and entered the production well via a high throughput channel (‘coning’). The magnitude of these effects were, however, sensitive to well perforation depth, the influence of which was subsequently studied systematically. Well perforation depth was found to determine the duration of these sinking and coning events in a non-linear manner.

Australia is a major exporter of wheat to South East (SE) Asia. Much of this wheat is low protein, fails in standard bake tests and is not traded as bread wheat. Some SE Asian bakeries observed that these doughs spread too significantly to be usable on current bread manufacturing lines. However, high-spread doughs are suited to sheeting lines and can produce high quality products. For confirmation, a pilot-scale dough sheeting line was constructed consisting of four roll-stands and a folder/lapper. Rollers were fitted with sensors to measure roll forces and dough sheet thicknesses. The first roll stand was also used to test flours for dough rheology. The sensors captured flour effects on dough flow quality during sheeting (‘sheetability’). The offline dough rheology data correlated with ‘online’ dough sheetability. The Australian flour doughs flowed more steadily through the roll stands than conventional bread doughs and also produced high quality sandwich breads.

EGR (Enhanced natural gas recovery) with CO2 sequestration offers the prospect of significant environmental and economic benefits by increasing gas recovery while simultaneously sequestering the greenhouse gas. Field-scale deployment is currently limited as the risks of contamination of the produced gas by injected CO2 are poorly understood. Reservoir simulations offer a method to quantify the risk but only if sufficiently accurate. For the first time, finite element simulations are presented for several EGR scenarios that incorporate the most accurate models available for fluid mixture and rock properties. Specifically, the GERG-2008 EOS (equation of state) is utilised to describe the supercritical fluid mixture's density, as are reference correlations linked to the most accurate experimental data available for diffusivity and viscosity. Realistic values for rock dispersivity and tortuosity determined from high-accuracy core-flooding and NMR (nuclear magnetic resonance) experiments were also integrated. The relative impacts of these properties were investigated for a benchmark layered reservoir with a quarter 5-spot well pattern. Recovery efficiency at different CO2 injection rates was also investigated and was determined to be the dominant consideration: a 100-fold rate increase improved recovery from 53% to 69% while CO2 breakthrough time decreased by less than expected. Collectively, these results emphasise the importance of accurate reservoir simulations for EGR.

Traditionally, chapattis are flatbreads made from atta (wholemeal Indian wheat flour). Non-atta chapattis have not been popular due to substandard product quality. To investigate what makes atta special for making chapattis, products were made using atta, Australian wholemeal wheat flour, gluten-free lupin flour, and a blend of lupin and wheat flours. Doughs were characterised by measuring strain-hardening and elastic recovery in compression and also bubble structures via 3-D X-ray micro-tomography. A method was developed to identify and separate bran, which appears as bubbles, in scans of doughs. Results highlighted the following: (1) elasticity of doughs is important for stabilising bubbles during rolling and baking, (2) atta doughs are low in strain-hardening but high in elasticity and retain bubbles the best after baking, and (3) lupins can be used to increase elasticity of Australian wheat flour doughs and to make gluten-free chapattis.

Current practices in testing flours call for measuring dough strength, not elasticity. Sheeting is a common method for processing developed doughs, the elasticity of which governs dough’s sheetability as dough springs back exiting rollers. To characterise dough sheetability, a study was conducted testing 18 different doughs made from six different flours. Each dough was sheeted using an instrumented sheeter and data for exit sheet thickness and roll forces were captured under a range of sheeting conditions. The true rheological properties of doughs were measured and used to calibrate the ABBM constitutive model for dough (1). Numerical simulations of sheeting operations were conducted; the R 2 coefficients between measured and predicted sheet thicknesses and roll forces (vertical and horizontal) were nearly all >0.9. Relaxation times were derived from dough model parameters and revealed that flour quality for dough elasticity should be assessed by examining moisture effects on dough relaxation time.

Chemical leaveners are used in doughs to generate carbon dioxide, as an alternative to yeast, in making a range of bakery products. In this study, the effects of fungal α-amylase and ascorbic acid on chemically leavened doughs were followed by measuring dough extensibility, true rheological properties, the amount of free liquid in doughs following ultracentrifugation and the quality of baked products. As with yeasted doughs, the bake qualities of chemically leavened doughs also improved in the presence of fungal α-amylases. The bake qualities were not affected when the equivalent amount of ascorbic acid was added. The differences in dough formulations were detected from measurements of true rheological properties, not from extensibilities of doughs. The amount of free liquid was larger and of lower viscosity in doughs containing α-amylases. The properties of the continuous liquid phase were found to be important in defining the rheological and baking qualities of doughs.

Solid–liquid pastes featuring high volume fractions of particulates are frequently used in ceramic forming operations. When pastes are used it is important that the particulate distribution remains uniform throughout the body. The stresses imposed during extrusion processing can, however, promote differential flow between the solid and liquid phases giving rise to product and processing problems. Reliable models for predicting phase distribution changes in these multi-phase systems are in their infancy. This paper reports progress towards developing simulation techniques and practical systems to verify the numerical approaches. Pastes containing glass spheres suspended in a highly viscous Newtonian fluid have been extruded at various speeds and solids loadings. Load and liquid content data are presented which form the basis for model verification. Soil mechanics approaches are used here to encapsulate the inherently multi-phase nature of these systems. The modified Cam–Clay model has been implemented in a finite element analysis simulation of ram extrusion using the ABAQUS platform. The simulation requires regular and extensive remeshing and monitoring of the conservation of mass. Predictions of extrusion pressures and deformation behaviour are compared with the experimental data for a series of square-ended and conical dies.

A Green function method is presented which enables computation of laminar flow of an incompressible Newtonian fluid in circular and annular pipes, subject to an arbitrary forcing periodic pressure gradient, in terms of Bessel functions. The response to a step change in pressure gradient in an annular pipe is presented. The method allows direct calculation of wall shear stress and flow rates generated by pulsed flows, which are of interest in fouling mitigation and cleaning-in-place systems.