[en] Highlights: • The effect of inclination on distribution parameter and drift velocity is studied. • Slug behaviors in different flow regions are investigated. • Inclination influences the void fraction and slip ratio. • Drift flux models for calculating void fraction are evaluated. • Correlations of frictional pressure drop are evaluated in different flow regions. - Abstract: A visualization-based investigation was carried out on slug behavior and pressure drop of air–water slug flow in a narrow rectangular duct with cross section of 43 mm × 3.25 mm under inclined conditions. The velocity and length of slugs were obtained through image processing. Based on the liquid Reynolds number, slug flow was divided into laminar flow region (Re_l < 3000) and turbulent flow region (Re_l ⩾ 3000). Experimental results showed that both the slug velocity and the slug length increased with the inclination angle increasing in laminar flow region, while they were nearly unvaried in turbulent flow region. The slug length and slug frequency decreased with the gas superficial velocity increasing or the liquid superficial velocity decreasing for all cases. For laminar flow, the predictions of frictional pressure drop by Chisholm model, Mishima–Hibiki correlation and Lee–Lee correlation could be significantly improved by replacing the void fraction with the ratio of the slug velocity divided by the gas superficial velocity, u_s/j_g; for turbulent region, all three models could well predict the experimental data if void fraction is calculated by the Jones–Zuber correlation

[en] Highlights: • Thermal–hydraulics design of a MSFR core. • Computation Fluid Dynamic (CFD) modelling. • Optimization of the geometry of the MSFR core cavity. • Fuel salt temperature and velocity distributions. • Sensitivity of the salt flow distribution to the reactor operating parameters. - Abstract: A thermal–hydraulics study of the core of the Molten Salt Fast Reactor (MSFR) is presented. The numerical simulations were carried-out using a Computation Fluid Dynamic code. The main objectives of the thermal–hydraulics studies are to design the core cavity walls in order to increase the overall flow mixing and to reduce the temperature peaking factors in the salt and on the core walls. The results of the CFD simulations show that for the chosen core design acceptable temperature distributions can be obtained by using a curved core cavity shape, inlets and outlets. The hot spot temperature is less than 10 °C above the average core outlet temperature and is located in the centre of the top wall of the core. The results show also a moderate level of sensitivity to the working point

[en] Highlights: • Detailed studies of using nanofluids in a PWR reactor are performed. • The Case-Bibi model is utilized to consider the gap conductance. • A considerable enhancement of heat transfer is accomplished. • The critical boric acid and relative power distribution are less impacted. - Abstract: In this paper we investigate the thermal–hydraulic and neutronic attributions of using nanoparticles in the primary cooling system of a VVER-1000 reactor. The coupled analysis of the nanofluid core is performed by using DRAGON, DONJON and a thermal–hydraulic model that solves the governing momentum, energy, and mass equations. The applied approach is validated by comparing the results with the final safety analysis report (FSAR) of the plant. Finally, critical boric acid, relative power distribution, pressure drop, and temperature distributions of fuel, clad and coolant are considered for water/Al₂O₃ nanofluid. It is observed that low volume fraction of the nanoparticles has a minimum impact in critical boric acid up to about 3% and relative power distribution about 2% at maximum while the heat transfer is enhanced in comparison to pure water

[en] Highlights: • Boiling incipience experiments were performed in a rectangular channel. • Four methods were adopted to judge the boiling incipience. • Experimental data obtained through different methods were compared with the classical correlations. - Abstract: To identify the discrepancy between different boiling incipience judgment criteria, a series of experiments on the boiling incipience are performed for water flow in a range of water mass flux varying from 100 to 1500 kg/(m² s), heat flux from 20 to 200 kW/m², inlet subcooling from 20 to 74 °C, and the pressure from 0.2 to 2 MPa. A parametric study has been conducted to investigate the effect of pressure, inlet subcooling, heat flux and mass flux. The entire experimental data obtained through different determination methods indicate that inception wall superheat is dependent on the inlet subcooling, heat flux and mass flux, but the variation of pressure does not lead to a significant change in boiling incipience. In addition, the comparison between experimental data gained from the different judgment criteria and boiling inception correlations does not present evident discrepancy, and the wall superheat at the location of boiling incipience in the present narrow rectangular channel has good agreement with the Thom correlation

[en] Highlights: • Multiphysics model for electrical, thermal and structural performance prediction. • Structural performance of PV modules is important under thermal cycling and cooling. • Methodology for coupling thermal and electrical model of PV modules. • Simulations done for four different full days representing different timings of a year. • Cooling effectiveness is most strongly dependent on incident solar radiation. - Abstract: The main performance metric of any PV device is its electrical power output. But the ability to predict its thermal and structural response under different environmental conditions are also important in order to estimate its overall performance and for useful life prediction and reliability analysis. In the current work, the development of a multiphysics model is presented which is capable of estimating the three dimensional thermal and structural performance as well as the electrical performance of a PV module under given meteorological conditions. The model is also capable of including the effect of module cooling. The thermal modeling has been carried out in ANSYS CFX CFD environment, the structural modeling has been done in ANSYS Mechanical FEA code and the electrical modeling has been developed in MATLAB environment. The electrical model used is an improved seven-parameter electric circuit model which is capable of better simulating the electrical performance of the module at low irradiance and high temperature conditions. A coupling methodology to include the effect of electrical performance of the PV module in the thermal model inside the CFD environment has also been presented in the paper. Using the developed model, the electrical, thermal and structural performance of a PV module with and without cooling has been analyzed for four different days representing different environmental conditions at Jeddah, Saudi Arabia

[en] Highlights: • A COP of 0.8 is achievable for a thermoelectrically-driven water chiller. • With two market available TEC modules with ZT around 0.7 sub-zero temperatures became applicable. • Forced air convection heat exchangers have better COP and CDP compared with natural convection. • A PID controller has several advantages against on–off controller for controlling TEC module. - Abstract: To study COP and other cooling parameters of a thermoelectically-driven liquid chiller, a 430 ml capacity liquid chiller incorporating two commercially available thermoelectric modules as its active components, has been designed, built and assessed. The system can use natural or forced air convection in heat exchangers attached to the thermoelectric module surfaces. The coefficient of performance (COP) and cooling down period (CDP) of the system for different thermoelectric input voltages have been measured. The COP of the thermoelectric chiller was found to be in the range 0.2–1.4 for forced convection and 0.2–1 for natural convection at a cooled liquid temperature of 10 °C and an ambient temperature of 18 °C. For the chiller, heat pumping capacity, minimum achievable water temperature, and temperature difference across the thermoelectric surfaces were investigated for input voltages of 3 V, 5 V, 7 V, 10 V and 12 V. Furthermore, as a basis for reliable and convenient control of the chiller, a proportional integral derivative (PID) controller has been proposed

[en] Highlights: • We presented performance evaluation approach for industrial inclined bed paddy dryer. • Specific electrical energy consumption was 1.44–1.95 MJ/kg water evaporated. • Specific thermal energy consumption was 2.77–3.47 MJ/kg water evaporated. • Dryer yielded 1–4% higher head rice at drying temperature of 38–39 °C than 41–42 °C. • Dryers should be operated at 38–39 °C for 1–4% higher head rice at reasonable energy. - Abstract: The performance evaluation of any industrial dryer regarding energy consumption and product quality should be assessed to check its present status and to suggest for further efficient operation. An investigation was carried out to evaluate the impact of drying temperature and air flow on energy consumption and quality of rice during paddy drying with industrial inclined bed dryer (IBD) with average holding capacity of 15 ton in the selected complexes of Padiberas Nasional Berhad (BERNAS)-the national paddy custodian of Malaysia. In reducing paddy moisture content (mc) from 22% to 23% wet basis (wb) down to around 12.5% wb, the final mc, the specific electrical (in terms of primary energy) and the specific thermal energy consumption were found to be varied between 1.44 to 1.95 MJ/kg water evaporated and 2.77 to 3.47 MJ/kg water evaporated, respectively. Analysis revealed that the specific electrical energy consumption was around 20% lesser and the specific thermal energy consumption of IBDs was around 10% higher during drying with air temperature of 41–42 °C than drying with 38–39 °C in reducing paddy mc from 22% to 23% (wb) down to around 12.5% (wb). However, paddy being with almost same initial mc dried using drying temperature of 38–39 °C, IBDs yielded 1–4% higher head rice yield while milling recovery and whiteness were comparable at acceptable milling degree and transparency. The bed air flows between 0.27 and 0.29 m³ m⁻² s⁻¹ resulted in higher head rice yield slightly while its effect on drying time was not prominent so much. For paddy with initial moisture content below 23% wb, it is recommended that drying air temperature should not be higher than 39 °C in order to maintain rice quality at reasonable energy consumption

[en] Highlights: • This paper proposes a new method to optimize a Switched Reluctance Motor (SRM). • A combination of SOA and GA with Finite Element Method (FEM) analysis is employed to solve the SRM design optimization. • The results show that optimized SRM obtains higher average torque and higher efficiency. - Abstract: In this paper, performance optimization of Switched Reluctance Motor (SRM) was determined using Seeker Optimization Algorithm (SOA). The most efficient aim of the algorithm was found for maximum torque value at a minimum mass of the entire construction, following changing the geometric parameters. The optimization process was carried out using a combination of Seeker Optimization Algorithm and Finite Element Method (FEM). Fitness value was calculated by FEM analysis using COMSOL3.4, and the SOA was realized by MATLAB. The proposed method has been applied for a case study and it has been also compared with Genetic Algorithm (GA). The results show that the optimized motor using SOA had higher torque value and efficiency with lower mass and torque ripple, exhibiting the validity of this methodology for SRM design

[en] Highlights: • We studied a thermosyphon solar water heater composed of high-performance components. • A differential equations solution technique is investigated. • The influences of the collector and storage losses on the system performance were examined. • The storage losses have more influence on the long-term performance. - Abstract: A glassed flat plate collector with selective black chrome coated absorber and a low wall conductance horizontal storage are combined in order to set up a high performance thermosyphon system. Each component is tested separately before testing the complete system in spring days. During the test period, effect of different inlet water temperatures on the collector performance is studied and results have shown that the collector can reach a high efficiency and high outlet water temperature even for elevated inlet water temperatures. Subsequently, long term system performance is estimated by using a developed numerical model. The proposed model, accurate and gave a good agreement with experimental results, allowed to describe the heat transfer in the storage. It has shown also that the long-term performances are strongly influenced by losses from the storage than losses from the collector

[en] Highlights: • We evaluated bending load effect on the failure pressure of wall-thinned pipe elbows. • Burst tests were conducted on real-scale elbow specimens with local wall thinning. • The tests were performed under combined pressure and load-controlled bending. • Load-controlled bending reduced the failure pressure of wall-thinned elbows. • Bending load effect was significant for opening-mode and intrados wall-thinning case. - Abstract: In this research, burst tests were conducted on real-scale elbow specimens, each with an artificial local wall-thinning defect, under combined internal pressure and constant in-plane bending load, as well as under simple internal pressure, to evaluate the effect of load-controlled bending load on the failure pressure of locally wall-thinned pipe elbows. Ninety-degree, 65A Schedule 80 elbows, with wall-thinning defects in the intrados and extrados, were used as specimens. The bending loads were in-plane opening- and closing-mode bending, applied in load-control mode. The results clearly indicated that a load-controlled in-plane bending load reduced the failure pressure of wall-thinned pipe elbows, in contrast to observations previously made under displacement-controlled bending conditions. The effect of the bending load was more significant for opening-mode than for closing-mode bending, regardless of the wall-thinning location in the elbow. Also, the effect was greater when the wall-thinning defect was located in the intrados region of the elbow, rather than the extrados region. Existing models that have been proposed to evaluate the failure of wall-thinned elbows under simple internal pressure conservatively predicted the failure pressure of elbows subjected to a combined internal pressure and load-controlled bending load