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In this paper, theoretical investigation of an integrated solar-powered cooling system consisting of commercial photovoltaic/thermal (PVT) collectors and an adsorption chiller is performed. The performance is investigated under different climate conditions of the Middle East such as Alexandria in Egypt, Dubai in United Arab Emirates and Riyadh in Saudi Arabia. System performance parameters including cooling capacities, chiller COP, solar COP, generated electric power and total system efficiency have been investigated. The results of the study for the month of July show that the maximum generated electric power is about 12.55 kW in Alexandria, while the maximum cooling capacity and COP are 8.1 kW and 0.43, respectively in Dubai. Furthermore, the average total system efficiency in a typical day in July is about 0.248, 0.288 and 0.275 in Alexandria, Dubai and Riyadh, respectively.

A novel CFD modeling approach was developed to investigate the hydrodynamics and mass transfer in a gas–liquid slug flowing through microscale coil and coiled flow inverter channels. One straight slug model was formulated by adding a virtual centrifugal body force. The model was validated in terms of the helicity and secondary flow magnitude. The secondary flow magnitude was shown to be a power function of the Dean number, and a new correlation was proposed. The mass transfer across the interface was compared to that obtained in previous studies. The new model described the temporal and spatial distribution of species in the slug reasonably well. The volumetric mass transfer coefficient kLa in the coil was found to be 1.5 times higher than that in the straight channel, and the enhancement in kLa reached a maximum at a modified Dean number of 1.2.

Dry reforming of methane (DRM) for syngas production has gained much attention because of its significant potential in greenhouse gas reduction and economic efficiency over steam reforming. The practical application of DRM has been hindered by problems of coking in cold spots, coking-induced blockage and pressure loss in the catalyst packed beds. The previous works developed a packed bed type microreactor with a blow-through channel, namely a catalytic wall-plate microreactor (CWPMR) to solve those problems. However, it did not outperform the conventional tubular packed bed reactor. Objective of this study is to process-intensify DRM by structuring CWPMR. A void space and micro-baffle were formed in the packed layer and in the blow-through channel, respectively. This study proposed the micro-structure to enhance convective heat and mass transfer, and resultant reaction efficiency. Particle-resolved CFD simulations verified the favorable effects of the micro-structure on flow distribution in CWPMR. Reaction experiments showed that the micro-structured CWPMR significantly outperformed the conventional reactor and reduced carbon deposition with the identical catalyst loading.

The object of the current work is to enhance diesel engine performance utilizing diesel/Jatropha biodiesel/n-butanol blends with the addition of carbon nanomaterials, which are mainly multiwalled carbon nanotubes (MWCNTs), graphene nanoplatelets (GNPs), and graphene oxide (GO). The results showed that Jatropha biodiesel and Jatropha biodiesel-diesel (JB20) mixed with GNPs, GO, and MWCNTs exhibited significant improvement in combustion and emission characteristics. The same findings are achieved with a Jatropha biodiesel-n-butanol mixture (JME40B) with the addition of these additives. The peak pressure and brake specific fuel consumption were higher compared to the base fuel. Additionally, the addition of a high blending ratio of n-butanol with Jatropha biodiesel with the existence of carbon nanomaterials has the potential to achieve new norms of NOx, CO, and UHC emissions while also keeping a high thermal efficiency level. Finally, the results illustrate that the concentration of 50 mg/L had maximum improvement in both the engine combustion and emission parameters.

The effects of baffles, flow conditions and fluid properties on wavy motion of falling film were examined experimentally and numerically. Visualization showed that the liquid film became wavier by increasing the baffle distance and by changing liquid from water to methanol in the range of Reynolds number less than 42. Subsequently, the falling film behavior was numerically investigated by adopting VOF method. The qualitative agreements under similar flow conditions well validated both of visualization and numerical methods. The numerical results showed that a higher baffle tended to cause film break-up while the break-up was prevented by increasing the flow rates. As Reynolds number increases, the liquid film became wavier and further surface deformation became obvious. Those results demonstrated that properly-baffled reaction plate could form a noticeably wavy and deformed but quasi-stable falling film at a given flow rate for an organic solvent. The amplitude of wavy falling film on the baffled plates was correlated with Reynolds number, Bond number and non-dimensional geometrical factors, while the thickness of the wavy falling film was correlated with the non-dimensional geometrical factors. It was finally suggested that the possible enhancement of gas absorption due to the surface deformation of liquid film is of further interest targeting process intensification.

Ultrafiltration has been utilized widely in the dairy industry processes such as the separation and concentration of protein whey solution. In such processes, the critical problem is the decline of permeate flux caused by membrane fouling. Several models have been proposed to explain the behavior of filtrate flux during filtration. Our prior work developed a model which divides the permeation process into two periods according to the dominant factor controlling the filtration resistance. The first period is pore blocking dominant and the second period is cake dominant. In this current work, an improved model is proposed. In the model, it is considered that membrane fouling by pore blockage mechanism and the development of compressible cake layer occur simultaneously. The pore blockage model and compressive yield stress model are modified and coupled to give the numerical prediction of the permeate flux. The calculation results are compared with experimental data of cross-flow ultrafiltration of the protein suspension system. The comparison indicates that entire permeation process is well presented by the proposed combined model. The results contribute a viewpoint for understanding the behavior of membrane and permeate flux in the filtration process.

In the dairy industry, whey protein is concentrated by means of cross-flow ultrafiltration. In this membrane process, the thickness of the cake layer is assumed to be controlled by the shear stress exerted by the feed flow. In our prior work, we developed a model for the cross-flow ultrafiltration of a whey suspension that incorporated the effect of this shear stress. In this study, the model is extended to consider the permeation process as two periods determined by the dominant factor controlling the filtration resistance. In the first period, pore blockage dominates while in the latter, cake deposition is dominant. The models for each period were combined using the results of the model for the first period as the initial conditions for the second period. The combined model was compared with experimental results of cross-flow ultrafiltration. Results show that the permeation process was well described under the conditions of this study by the combined model and the possibility of the application of the model to the cross-flow ultrafiltration system was indicated.