Influence of innovative hydrogen multi strut injector with different spacing on cavity-based scramjet combustor

In this study, the flow dynamics with finite volume approach on commercial software Ansys-Fluent 20.0 to solve the compressible two-dimensional fluid flow with Reynolds Average Navier Stokes equation (RANS) equation by considering the density-based solver with Shaer stress transport model (SST) k- ω turbulent model. The species transport model with volumetric reaction and finite rate/eddy dissipation turbulence chemistry interaction is adopted to study the combustion phenomena. Additionally, the effect of spacing between the struts on the flow characters and performance of the combustor is studied by increasing the spacing of struts from 1 mm to 4 mm for each increment of 1 mm. It is found that the multi strut improves the mixing and combustion efficiency compared with that of the single strut owing to the formation of a significant separation layer, resulting in multiple shocks, vortices, and a larger recirculation zone. However, when the spacing of struts is increased further, the performance of the combustor is found to be deteriorating owing to the formation of larger separation layers. The recirculation zone is significant when the strut spacing is minimal and shrinks and restricts itself within the cavity when spacing is increased. So, for better performance of combustor, multi strut with minimum spacing is preferable.

Advances and Applications of Hollow Fiber Nanofiltration Membranes: A Review

Hollow fiber nanofiltration (NF) membranes have gained increased attention in recent years, partly driven by the availability of alternatives to polyamide-based dense separation layers. Moreover, the global market for NF has been growing steadily in recent years and is expected to grow even faster. Compared to the traditional spiral-wound configuration, the hollow fiber geometry provides advantages such as low fouling tendencies and effective hydraulic cleaning possibilities. The alternatives to polyamide layers are typically chemically more stable and thus allow operation and cleaning at more extreme conditions. Therefore, these new NF membranes are of interest for use in a variety of applications. In this review, we provide an overview of the applications and emerging opportunities for these membranes. Next to municipal wastewater and drinking water processes, we have put special focus on industrial applications where hollow fiber NF membranes are employed under more strenuous conditions or used to recover specific resources or solutes.

Double-diffusive depletion of layers in hydrothermal systems

<p>In hydrothermal systems, the circulation of water through the porous matrix is strongly influenced by the joint effects of heat and salinity. Because of phase separation, layers of different salinities and temperature are thought to form, but their stability or their typical lifetime remains unclear. Moreover, the dynamics of heat transport across such a layered system is considerably enriched by double diffusive effects due to the slower diffusion of salinity relative to heat. Here, we study numerically the time evolution of an ideal two-layer configuration where a heavy layer of warm and salty water is overlain by a light layer of cold and fresh water. Thermal convection quickly develops in each layer and maintains a thin diffusive interface between the layers. There is long-standing controversy on the temporal evolution of such a system. Although Griffiths (1981) found experimentally that the sharp interface seemed to persist indefinitely, Schoofs & Hansen (2000) reported via numerical simulations systematic depletion and vanishing of the layers. We resolve this apparently inconsistency. In our simulations, we find systematic depletion of the two-layer initial condition in all cases. However, the timescale over which it occurs depends strongly on the ratio between salinity and temperature contributions to density. When salinity is weakly stabilising, thermal convection and layers are maintained over (very long) diffusive timescales. When salt is strongly stabilising, however, convection becomes quiescent over much shorter times and the sharp interface between layers is quickly diffused away. We determine scalings on the lifetime of the layers in both regimes as a function of the governing parameters.</p>

An automated centrifugal microfluidic assay for whole blood fractionation and isolation of multiple cell populations using an aqueous two-phase system

This paper describes an advanced on-chip whole human blood fractionation and cell isolation process combining an aqueous two-phase system to create complex separation layers with a centrifugal microfluidic platform to control and automate the assay.