In this study, a numerical and experimental analysis of a solar collector with roughness elements in the form of stainless-steel scourers on the absorber surface is presented. According to the location type and number of the stainless steel scourers, the absorber surfaces are referred to as the complex surface (C1), less complex surface (C2), and flat surface (C3). A Computational Fluid Dynamics (CFD) analysis was carried out using ANSYS-CFX-R18.2 commercial software. The results were verified with the experimental study. After the numerical study was confirmation with the experimental study, then the detailed investigation was performed by numerical simulations. The extracted results of the numerical and experimental analysis concerned the air temperature and velocity, and thermal efficiency, which varied with respect to the type of collector. As a result, the C1 type yielded the highest air velocity and air temperature, while the lowest values of air velocity and temperature were recorded for the C3 type, according to both the numerical analysis and experimental tests. This trend was similar for the efficiencies. The efficiency was nearly 80% for collectors with stainless-steel scourers, whilst it was 55% for the flat plate collector. The results showed that the experimental and numerical results agreed well.

Expanded clay (exclay) aggregate and cherry tree resin are used in this study to produce a lightweight construction material. Based on the grain diameter, exclays are classified as d = 2–4 mm and d = 4–6 mm. Cement is added to each group as the binder material. The exclay ratios vary as 10%, 20%, 30%, 40% and 50% of the total volume in the samples. The cherry tree resin is poured into the concrete mixture with a ratio of 1% and 1.5% of cement + exclay mixture in order to form artificial pores in each sample group. The produced samples are subjected to some tests, such as thermal conductivity, water absorption and compressive strength. It is determined that due to the increase in exclay ratios and particle diameter, there is an increase in porosity along with water absorption, but there is a decrease in density, thermal conductivity and compressive strength. Hence, these newly produced concretes are recommended for panel walls, brick, concrete briquettes, inner and outer plaster and concrete partition elements.

This study presents a three-dimensional transient Computational Fluid Dynamics (CFD) analysis of a Venturi injector system used in a textile machine for removing excess water from fabrics after dyeing or washing processes. The main objective is to determine the optimum operating conditions by investigating the coupled effects of nozzle diameter and inlet pressure on pressure distribution, velocity field, and suction performance. Numerical simulations were performed for three nozzle diameters (d_n = 14 mm, 15 mm, and 16 mm) and three inlet pressure values (P_i = 10 bar, 12 bar, and 15 bar). The results show that the Venturi injector performance is highly sensitive to the interaction between geometric and operating parameters. Increasing the inlet pressure from 10 bar to 15 bar resulted in approximately a 20% increase in maximum velocity and a 40–45% increase in vacuum pressure in the suction line. Among the investigated configurations, the nozzle diameter of 15 mm provided the most balanced flow structure, producing the highest pressure drop at the throat and the most stable suction behavior. Transient analyses revealed that suction formation occurs rapidly after flow initiation and remains stable throughout the operation period, indicating hydrodynamically stable injector performance under optimal conditions. The optimum operating point is identified as a nozzle diameter of 15 mm and an inlet pressure of 15 bar, where suction capacity is maximized and energy losses are minimized. The results provide a quantitative design guideline for the optimization of industrial Venturi injector system used in textile processing applications.

Jet impingement is a widely utilized technique in engineering, particularly for cooling high-temperature systems like aircraft engines and electronic devices. This study employs numerical analysis to examine the flow dynamics of dual impinging pulsating nanofluid jets, utilizing the ANSYS software platform. This research examines the combined impact of key parameters, including jet geometry, pulsation frequency and amplitude, nanoparticle volume concentration, and Reynolds numbers, on the efficiency of heat transfer. The impact of aluminum oxide (Al₂O₃) nanofluids with varying concentrations (1%, 2%, 4%, and 5%) on thermal performance is assessed. The findings of the study demonstrate that the pulsating jets generate bidirectional swirling flows and reverse vortices upon impact with the surface, resulting in notable enhancements in local heat transfer rates. These vortices expand and form wall jets, which contribute to an increase in the heat transfer coefficients and Nusselt numbers. The simulations demonstrate that higher pulsation frequencies (30 Hz) result in a 10% increase in heat transfer efficiency compared to lower frequencies (10 Hz). This is attributed to enhanced flow dynamics and improved heat distribution. Moreover, the incorporation of nanoparticles markedly enhances heat transfer efficiency. The Nusselt numbers were observed to increase by 18% when the concentration of nanoparticles reached 5%, in comparison to plain water. Additionally, the study underscores the significance of jet spacing, wherein an optimal separation distance of 100 mm between the dual jets was identified as a means of maximizing heat transfer by fostering effective vortex interactions. Higher Reynolds numbers contribute to the formation of thinner thermal boundary layers, thereby facilitating increased heat transfer rates, particularly at the stagnation points where the flow impinges directly on the surface. Overall, the study demonstrates that substantial enhancements in heat transfer can be achieved by optimizing key parameters such as pulsating frequency, amplitude, nanoparticle volume concentration, and jet distances.

This work investigates approaches to enhance the thermal performance of U-tube heat exchangers by coupling them with phase change materials (PCMs) enhanced with Al2O3 nanoparticles. The focus is on investigating how nanoparticle addition and wavy tube configurations influence the melting behavior. A numerical finite element model was validated against a reference study, confirming its accuracy. The incorporation of Al2O3 nanoparticles (0%, 1%, and 2%) led to a substantial improvement, reducing melting times by up to 80%. Notably, the wavy tube system with 2% nanoparticle-enhanced PCM demonstrated superior performance. To circumvent the significant computational expense associated with finite element analysis, an Adaptive Network-Based Fuzzy Inference System (ANFIS) was employed as a surrogate model. With a high prediction accuracy (R² > 0.997) for melting dynamics, the ANFIS model was then employed for a detailed optimization analysis. The optimization identified an ideal nanoparticle concentration of 3.50%, which minimizes the melting time to 263.63 seconds under wavy tube conditions. The findings underscore the potential of a hybrid FEA-ANFIS methodology, suggesting that a synergistic combination of nanotechnology, advanced geometries, and artificial intelligence offers an effective approach to improving the design and operational efficiency of thermal energy storage units.

The physical characteristics of gypsum plaster composites made from agricultural wastes of pine cones (PCs) and pine resin (PR), as sustainable substitutes for traditional natural fillers, are examined in this work. Particle sizes of 3–5 mm, 0–3 mm, and powder were used to classify the PCs after grinding. First, gypsum plaster was replaced with PC particles at 20%, 40%, 60%, and 80% by weight for each group to produce resin-free specimens. To create artificial porosity and improve the matrix’s binding strength, 1% PR by total weight was then added to duplicate mixes, yielding 24 different sample combinations. In resin-free samples, the addition of 3–5 mm, 0–3 mm, and powder PC (in ratios ranging from 20% to 80%) reduced the thermal conductivities by 35.16%, 33.84%, and 34.97%, respectively, and the compressive strength values by 82.00%, 77.18%, and 77.50%. Further decreases in thermal conductivity (29.36%, 32.05%, and 33.66%) and compressive strength (76.89%, 75.64%, and 75.48%) were observed in PR-modified samples. The results show that adding PCs and PR to gypsum plaster considerably improves the plaster’s thermal insulation while marginally reducing its compressive strength loss.