Numerical simulation of two-phase mass transport in three-dimensional naturally fractured reservoirs using discrete streamlines

Simulation of multiphase mass transport in large field-scale heterogeneous, naturally fractured reservoirs with common grid-based methods is very time consuming and costly. An in-house streamline-based simulator is extended to simulate two-phase flow of oil and water in 3D heterogeneous, naturally fractured reservoirs. Different waterflooding problems have been simulated in 2D and 3D fractured reservoirs, and their results are compared with those of the grid-based commercial software. It has been shown that the streamline-based simulator can predict the results of the grid-based software with an acceptable accuracy, while its computational time and required memory is exceptionally less than the grid-based method.     

沉积岩和火成岩对γ射线的吸收及散射的比较研究

介绍沉积岩（Ｓｉｔｉｏｎｅ和Ｃｏｎｇｌｏｍｅｒａｔｅ）和火成岩（ａｎｄｅｓｉｔｅ和ｆｅｌｓｉｔｅ）的γ射线的衰减系数与散射系数的测量方法和测量结果。四种材料均制成颗粒粗细不同的粉末，在制成样品。颗粒的尺寸有：０．１７、０．１３、０．０９５、０．０３５、０．０６３ｎｍ五种。同时也测量上述品种的天然岩石的衰减系数与散射系数。使用６０Ｃｏ、１３７Ｃｓ、１３３Ｂａ等γ射线源，能量在０．３６到１．３３ＭｅＶ范围。详细地研究了线性衰减系数μ，质量衰减系数μ／ρ、弛豫长度冲及侧边散射系数φ与颗粒直径ｄ、样品密度ρ和γ射线能量是Ｅ的关系。发现线性衰减系数与ｄ和Ｅ成反比与ρ成正比，而侧边散射系数与ｄ和Ｅ成正比但与ρ成反比。比较此两大类岩石的μ和φ差异的原因。实验的结果认为这些材料可用于屏蔽γ射线。     

Improving outdoor air quality based on building morphology: Numerical investigation

Due to rapid urbanization around the world, high concentrations of vehicular pollutants have deteriorated the outdoor air quality, which can affect the physical and psychological well-being of humans. Numerous strategies have been proposed to overcome these harmful impacts by improving the dispersion of air pollutants. Consequently, a question arises regarding the potential effects of building morphology on the dispersion of pollutants. Subsequently, transient three-dimensional Computational Fluid Dynamics (CFD) simulations are performed to examine the effect of building morphology on PM₁₀ dispersion. Eleven cases with various prototypes and morphological methods are compared with a simple building form to identify the patterns of PM₁₀ dispersion within a given time sequence under a prevailing inflow condition. The results indicate that the different designs of building morphology with varying Relative compactness (R_C) indicator highlight the importance of considering morphological factors to improve outdoor air quality. In addition, the proposed prototypes can reduce PM₁₀ concentrations by approximately 30%–90% at specific points in the studied time sequence. In particular, the vertical, horizontal, and grid folded prototypes can be considered more effective as an approximate decrease between 70% and 90% in PM₁₀ concentrations is observed, which reflects the influence of building morphology on improving outdoor air quality.     

Performance enhancement of direct methanol fuel cell using multi‐zone narrow flow fields

New serpentine and spiral flow field configurations were developed to enhance the performance of direct methanol fuel cells (DMFCs). The new configurations are based on two primary concepts, namely, narrowing the flow field and partitioning the total active area of the fuel cell. Three flow channel heights of 0.8, 0.4, and 0.2 mm were investigated in serpentine and spiral flow fields. The main active area is considered a single zone and is partitioned into two‐ and four‐zone designs while maintaining the total inlet mass flow rate of the reactant and oxidant. To determine the performance parameters of the newly proposed designs, a three‐dimensional single‐phase isothermal model was developed, numerically simulated, and validated through experimental measurements. The findings of the current study indicate that a serpentine flow field configuration with a channel height of 0.2 mm and two zones attains an enhancement of the net power density of 37% compared to a conventional single‐zone design with a flow channel height of 0.8 mm. Similarly, for a spiral flow field design, the maximum net power density increased by 26% using a two‐zone configuration with a channel height of 0.2 mm, in comparison to the conventional design of a single‐zone and a flow channel height of 0.8 mm. The newly developed designs utilize the lower height of the flow fields to decrease the dimensions of the fuel cell stacks and reduce the material costs required.     

An iterative code to investigate heat pump performance improvement by exhaust gases heat recovery

The race between the development of technologies and energy demand has drawn the guidelines of energy strategies for the next two decades. Indeed, the governmental organizations as well as the private sectors are spending huge effort to come up with new adequate strategies that allow to decrease energy consumption. Having said that, heat pump becomes an essential system in our daily life not only in residential building but also in hospital, industrial and touristic building. Nonetheless, (HP)s have very high energy consumption rate. Thus, and to be in line with the new trends in energy strategies, it is convenient to find new methods to enhance the performance of heat pump in order to reduce energy consumption. In this frame, the present paper suggests an approach to enhance the performance the heat pumps using the heat recovery from generators. For this purpose, an in-house code is developed allowing to simulate two new proposed systems (condenser upstream exhaust gases heat recovery system (CU-EGHRS) and condenser downstream exhaust gases heat recovery system (CD-EGHRS). It has been shown that the increase in the performance of the heat pump depends on the capacity of the generator. Also, the CD-EGHRS is shown to be the best. For instance, in the case of a 15 kVA generator, the enhancement could reach 42% for the CD-EGHRS. This enhancement increases to 5640% in the case of a 180 kVA generator.     

Probiotic yoghurt functionalised with microalgae and Zedo gum: chemical,microbiological, rheological and sensory characteristics

In this study, using a central composite design, the effects of addition of Spirulina platensis and Zedo gum to plain and probiotic yoghurt samples were investigated during storage. Lactobacillus paracasei proliferation was directly dependent on the addition of microalgae and was inversely affected by storage time. Probiotic samples containing S. platensis showed the highest antioxidative activity. Maximum stability was obtained at higher amounts of Zedo gum, while organoleptic and rheological attributes improved at 0.25% Zedo gum. Given the importance of probiotic viability, supplementation of probiotic yoghurt with Zedo gum/S. platensis may be consideredas a novel nutraceutical formulation.