Topology optimization of heat and mass transfer problems in two fluids—one solid domains

Abstract

Among various topology optimization methods used in fluid flow problems, density approach has gained more interest compared to other techniques as level set approach, topological derivative technique, and phase field method. The key part of density approach is the penalized interpolation function, which forces progressively porous cells made of fluid and solid simultaneously to belong discretely to fluid or solid sub-domains. However this type of problem was only solved in mono-fluid domains, in which the method accounts for the distribution of a single fluid and a single solid. The actual work aims to extend topology optimization in fluid flow problems to bi-fluid domain. A new interpolation function was developed for this purpose. Furthermore a penalization function was integrated in the multiobjective function, which ensure that each fluid takes its own path in the device, while maintaining a minimal required solid thickness between the channels of different fluids. The results showed the capacity of the proposed method to deal with multiple fluid phases in minimizing the pressure drop while maximizing heat exchange between different flows. The main conclusion is the potential of density approach to be applied on optimization of heat exchangers.     

Parallel application sampling for accelerating MPSoC simulation

Multi-processor system-on-chip (MPSoC) simulators are many orders of magnitude slower than the hardware they simulate due to increasing architectural complexity. In this paper, we propose a new application sampling technique to accelerate the simulation of MPSoC design space exploration (DSE). The proposed technique dynamically combines simultaneously executed phases, thus generating a sampling unit. This technique accelerates the simulation by allowing the repeated combinations of parallel phases to be skipped. A complementary technique, called cluster synthesis, is also proposed to improve the simulation acceleration when the number of possible phase combinations increases. Our experimental results show that this technique can accelerate the simulation up to a factor of 800 with a relatively small estimation error.     

Transformation of the Β-Triketone Pesticides Tembotrione and Sulcotrione by Reactions with Ozone: Kinetic Study,Transformation Products,Toxicity and Biodegradability

Rate constants between ozone and triketone herbicides, tembotrione and sulcotrione, were determined between pH 2 and 12. Both compounds are completely transformed within seconds by ozone under real water treatment conditions. A reaction pathway was proposed based on the identification of transformation products. Toxicity evaluation using Vibrio fischeri test showed that a residual toxicity remained even after degradation of the major by-products, but biodegradation significantly increased from 50% to 70% for molar ozone to pesticide ratios from 0 to 2. Thus, ozonation coupled with biological treatment would drastically reduce the risk associated to the presence of triketone herbicides.     

Composite delamination modelling using a multi-layered solid element

This paper focuses on the latest development of a solid hexahedron element for composite delamination analysis. The 8-node solid is derived from a 20-node hexahedron. It is transformed into two physical independent 4-node shell elements according to the propagation of delamination process within the element.     

Modeling of power devices with drift region integrated microchannel cooler

This paper introduces the DRIMCooler—an innovative concept allowing to integrate the heat exchanger directly into the active region of a vertical power device. Based on the realization of vertical edge terminations and the use of dielectric coolant fluid circulation, arrays of through wafer channels are etched in the silicon substrate offering a large heat exchange coefficient while minimizing the pressure drops. The concept is introduced and discussed with respect to the technological and the electrical issues. The thermal analysis is based on numerical models and simulations. The obtained results show excellent thermal and hydraulic performances of the DRIMCooler concept.     

Recycled materials in railroad substructure: an energy perspective

Railway Engineering Science - Given that the current ballasted tracks in Australia may not be able to support faster and significantly heavier freight trains as planned for the future, the imminent...