Engineering and Technology Journal

As far as thermal insulation is concerned, phase change materials (PCM) have a very good potential to be excellent insulation materials due to their thermal properties like low thermal conductivity and high latent heat. The researchers started to incorporate the walls and windows with PCM to reduce the internal surface temperature and indoor temperature of the room. This paper focuses on double and triple-glazed windows’ thermal performance, different filling insulation materials, ventilation windows, and thermochromic glazing. In addition, a detailed discussion on the effect of changing the thickness and the thermal characteristics of the PCM and its influence on the internal surface temperature, temperature time lag, and other parameters such as total energy transmitted and indoor temperature. Previous studies have shown that including PCM in triple-glazed windows decreases the temperature of the inner surface by 2.7℃ and 5.5℃ compared to double-glazed windows with PCM and triple-glazed windows. Utilizing ventilation during summer nights saves 46% on cooling energy. By using two different PCM melting temperatures, the maximum interior and surface temperatures are reduced by 6℃. The integrated PCM blind system prevented the room occupants from being exposed to direct sunlight. Finally, additional recommendations were made based on the identified research needs.

This research work presents a gas turbine performance investigation. Researchers have put efforts into this field of study; however, the influence of the concurrence of variable inlet guide vane (VIGV) drift, fouling, and erosion on the three-shaft gas turbine’s performance during part-load operation has remained unexplored. Therefore, this study addresses this gap. First the gas turbine design point and off-design performance model have been developed by utilizing the original engine manufacturer data provided. The accuracy of the models was validated, and the maximum mean absolute percentage error of the design point performance model is shown at exhaust temperature prediction, it is about 1.74%. The off-design performance model was also validated with the power output versus ambient temperature and efficiency versus operating curves. At each operational point, the power output versus ambient temperature error from the validation data was 0.02%, while the efficiency versus ambient temperature error was 4.5%. After the validation, the engine model was subjected to the concurrence of variable inlet guide vane drift, fouling, and erosion conditions to simulate the degradation state. The results show that the highest isentropic efficiency deviation due to component faults occurred in the upstream components, specifically in the low-pressure compressor’s (LPC) isentropic efficiency. The deviation recorded due to the concurrence of VIGV drift at -6.5° and 100% fouling severity is -11.47%, whereas 9.65% is the LPC isentropic efficiency deviation recorded when VIGV drift at -6.5° and erosion at 100% severity level simultaneously occurred. In addition, the effects of the faults above on gas path measurements were simulated, and the highest measurement deviation was observed when simultaneous LPC fouling and -6.5% VIGV drift occurred. Among the measurements, the highest deviation was observed in the exhaust temperature and thermal efficiency, about 9.23% and -7.35%, respectively.

Despite water covering more than two-thirds of the planet, improving potable water production technologies is a significant issue because of the increased demand for treated water. Solar desalination presents a simple, costless energy and friendly technology which utilizes solar energy and gives great incentive to decrease pollution effects produced by burning fossil fuels. In order to address the global drinking water shortage, particularly in rural and distant locations, this technique can be employed to give pure water to people using a solar still, which in many respects, is one of the most significant feasible uses of solar energy and perfect source of fresh water. However, due to the low productivity of conventional solar still, numerous experiments have been done to increase the daily output of solar stills by employing numerous active strategies to produce far more evaporation and condensation than a simple standard-type distiller. This work highlights the recent methods used for enhancing water productivity and their roles in augmentation productivity, performance, and thermal effectiveness of various solar distiller designs based on previous studies. Future suggestions based on identified research needs were made. This review is considered a reference guide to focus on the most efficient techniques.

The cooling of solar photovoltaic (PV) cells is reviewed in this study. The critical analysis aims to increase PV cell life span and electrical efficiency. To improve the caliber of future studies, this paper examines the implications of earlier studies as well as technical specifics for optimization. Additionally, some of the benefits and drawbacks of various cooling methods are explored. The PV cells cool rate and the PV system's jet impingement cooling technology in PV systems are more effective than any conventional PV cooling systems. Phase change material (PCM) is one of the effective methods used to cool PV cells, as it supporting PV cell cooling in both hot and cold environmental circumstances is beneficial. PCM is appropriate for the cooling application of PV cells due to the requirement of local temperature variation. Many researches and experiences on a different ways of cooling PV collector had been studied to analyze the behavior of PVT systems. Jet and Nanoparticles with PCM are the main ways of cooling and will be discussed in this paper. Lastly, future recommendations based on identified research gaps were suggested. In future work, it is recommended to use jet impingement cooling with PCM together for the PVT system. The proposed system integrates two types of the cooling system with a PV system, the advantage of using jet impingement cooling can result in low average cell temperature for PV cells, and PCM as storage energy with Nanoparticles to enhance the thermal conductive of PCM.

The present study utilizes the commercial software ANSYS-Fluent to explore the influence of the geometry of thick S- S-series airfoil on the near-wake region. Four different S-series airfoils, namely S809, S811, S814, and S818, were investigated at a wide range of angles of attack, which were varied from 0 degrees to 20 degrees with an increment of 2 degrees and at a Reynolds number based on chord length Re = 1x106. Analysis of the resultant data revealed that the aerodynamic
performance of the S811 and S818 airfoils superseded that of the S809 and S814
airfoils. To illustrate, at the critical angle of attack, S811 and S818 were observed
to possess the maximum lift and minimum drag coefficients. Furthermore, in the
range of attack angles between 10 and 16 degrees, these airfoils consistently
demonstrated lower drag than the others tested, enhancing overall aerodynamic
performance. These findings underscore the significant role played by airfoil
geometry in influencing aerodynamic performance and provide insights into
optimal design parameters for wind turbine blades, particularly highlighting the
advantages of the S811 and S818 airfoil shapes. In addition, the effect of the
unsteady structures in the near-wake zone behind the trailing was also evaluated
through turbulence kinetic energy contours. The results revealed a decrease in
turbulence kinetic energy when the S811 and S818 airfoils were placed in a crossflow
compared to the S809 and S814 airfoils. This indicates that the strength of
the vortex shedding of these airfoils is lower than that of the S809 and S8014
airfoils.

Experiments are conducted to investigate the heat transfer and pressure drop characteristics of corrugated tubes and rod baffles in a shell-and-tube heat exchanger. One of the effective techniques to improve heat transfer is to use corrugated tubes. This article investigates rod baffles with varied corrugation depths and corrugated tubes for (1 start). In the heat exchanger's shell side, where a constant wall temperature was attained on the tube side, water was employed as the working fluid after being heated at the wall. Corrugation ratios (e/dh) of 0.1 and 0.13, pitch (p) of 10, 20, and 30mm, and two types (x/d) of 1.25 and 1.375 were used. The study was conducted throughout the Reynolds number turbulent range (4,000 to 24,000). The results manifested that the average Nusselt number of the corrugated tubes (pitch-10mm) for (x/d=1.25) increased by 25 and 55 percent for the corrugation depths of 0.1 and 0.13, respectively. The average Nusselt number for (x/d=1.375) is increased by 38% and 59% for the corrugation depths of 0.1 and 0.13, respectively. Nevertheless, the average friction factor of the corrugated tube with (e/dh) = 0.1 and 0.13 is higher than that of the smooth tube by 66% and 130%, respectively, and it decreases as the corrugation pitch and (x/d) are increased. When a corrugated tube and a rod baffle with a corrugated depth (e=2.1 mm) and pitch (p=10 mm) were used, the thermal enhancement factor was 1.9 for (x/d=1.25) and 1.97 for (x/d=1.375) at the same pumping power.

This paper presents analytical solutions for the buckling of thick beams. The Bernoulli-Euler beam theory (BEBT) overestimates their critical buckling load. This paper has derived a cubic polynomial shear deformation beam buckling theory (CPSDBBT) from first principles using the Euler-Lagrange differential equation (ELDE). It develops closed-form solutions to differential equations using the finite sine transform method. The formulation considers transverse shear deformation and satisfies the transverse shear stress-free boundary conditions. The governing equation is developed from the energy functional, Π, by applying the ELDE. The domain equation is obtained as an ordinary differential equation (ODE). The finite sine transformation of the ODE transforms the thick beam, which is considered an algebraic eigenvalue problem. The solution gives the buckling load Nxx at any buckling mode n. The critical buckling load Nxx cr occurs at the first buckling mode and is presented in depth ratios to span (h/l). It is found that and agrees with previous solutions using shear deformable theories. For /010.,hl=(a moderately thick beam), the Nxx cr is 2.50% lower than the value predicted using BEBT, confirming the overestimation by BEBT. The Nxx cr /010.,hl=agrees with previous solutions, implying the shear deformation has been adequately accounted for, and the BEBT overestimates the Nxx cr. The value of Nxx cr found agrees with previous values in the literature.

Effective structural monitoring maximizes efficiency in wind turbines, a crucial renewable energy asset. Using advanced condition monitoring techniques is crucial for reliability. This experiment shows how to use DWT and FFT for wind turbine blade fault detection. DWT allowed for multiresolution analysis of vibration signals from a healthy and eroded lab-scale turbine blade under controlled wind speeds. A 5-level DWT decomposition identified frequency sub-bands with localized fault information. The FFT post-processing of level 5 approximation coefficients revealed precise modal frequency shifts between blade states. The healthy blade showed a dominant 16 Hz mode that matched operational dynamics. Erosion caused a 24 Hz fault signature that was not present in the intact blade. Automated blade state classification was 98% accurate with 8 Hz modal separation. DWT's high sensitivity comes from nonstationary signal filtering and FFT's high-resolution spectral quantification. Comparative metric analysis confirmed DWT's superiority over FFT and statistical methods. The integrated approach combined complementary techniques to detect small defects that were previously unnoticeable. This study confirms the effectiveness of using DWT's strengths for monitoring wind turbine structural health in the future. The approach enables switching from time-based maintenance to data-driven prognostics, improving reliability by detecting failure precursors early. This study confirms DWT's effectiveness in identifying wind turbine blade faults and advancing critical techniques to prevent catastrophic failures

A significant heat flux affects the efficacy and durability of most equipment. Cooling these devices is the primary concern, prompting specialists to propose and investigate various solutions. For these applications, microchannels are regarded as a possibility. Experiments were conducted in this study to determine the effect of an electroplating coating on the characteristics of a single-phase flow. As the working fluid for the experiments, deionized water was used. During the investigations, a microchannel of 0.3mm width and 0.7mm depth with an average roughness of 18.64 nm was machined; the inlet temperature was maintained at 30°C, and the Reynolds number ranged from 109.2 to 2599. According to the results, the correlation between the fanning friction factor and laminar and turbulent flows can predict experimental findings with high precision. In addition, an increase in the Nusselt number correlates with an increase in the Reynolds number.When compared to a conventional microchannel, the models with an Al2O3 cladding have a fanning friction factor that is much greater. According to the results, a reliable correlation can be used to precisely estimate the friction factor of typical Al2O3-coated microchannels. The results demonstrated that the average value of the maximum thermal performance value was approximately 1.19 at low Reynolds numbers between 240-480 and then decreased as Reynolds numbers increased.

Wind tunnels are essential for examining aircraft model aerodynamics, accurately simulating real-world conditions, and enhancing design and performance evaluations. This study introduces a novel technique to improve the time and accuracy of stress distribution forecasts in wind tunnel simulations. This method combines Finite Element Analysis (FEA) with two regression models: Support Vector Machine (SVM) and k-Nearest Neighbors (kNN). The investigation begins with a thorough analysis of ANSYS fluent flow data, which reveals intricate fluid dynamics details within the wind tunnel. A comparative analysis of stress projections, supplemented by Root Mean Square Error (RMSE) metric, demonstrates the proposed methodology’s viability. High accuracy is noted in the SVM-based model, as evidenced by its 2.1% RMSE, which surpasses the kNN model's 5.6% RMSE. Notably, the stress distribution calculation took almost 2 hours in ANSYS.In contrast, it required only 10 seconds in SVM and 3 seconds in kNN, showcasing the time-efficient attributes of these models where they solely depend on the trained data. Moreover, the computational efficacy of the SVM and kNN models is highlighted, emphasizing their flexibility in stress analysis. This integrative approach introduces a promising potential in engineering simulations, yielding precise stress distribution forecasts that have the potential to advance aircraft design methodologies and wind tunnel evaluations.

This study investigates the influence of ceramic coating on diesel engine efficiency through comprehensive analysis. The investigation was conducted on a four-stroke Kirloskar TV1 diesel engine. The study further examined the effects of employing an 8000 Gauss magnetic field and exhaust gas recirculation on engine performance. The surfaces of the head of the cylinder, the piston, and both the inlet and exhaust valves are then covered with nano-ceramic materials. Atmospheric plasma spray-created nanostructured thermal barrier coatings (TBCs). The feeding powder type is 7% Y2O3-ZrO2 with a particle size of less than 100 nm yttria stabilized zirconia (YSZ) nano X (S4007) ceramic surface coating (350 μm). Bond powder (NiCrAlY) Amdry 962, ranging from 56 to 106μm, has been utilized as a metal bonding coat (150 μm). The results show that the temperature of engine exhaust rises after coating, resulting in a decrease in fuel consumption by 14.22 %. The effect of biofuels on the performance of a compression ignition engine running on diesel fuel was examined. The testing findings revealed that brake thermal efficiency (BTE) improved by 20.5%, and brake-specific fuel consumption (BSFC) decreased by 18.1%. When the load goes up from 50 to 100 percent, however, 38.8 percent and fewer CO percent are observed for the B10+10EGR+8000 Gauss and 0.5 mm coated engine. Also, acceptable increases in emissions were observed in CO2 levels. Diesel and the B10+EGR10+8000 Gauss un-treatment engine's NOx emission values rise by 49.15 percent and 45 percent, respectively, after the load goes up 75 percent.

Various industrial applications, including rotating and reciprocating machinery, depend on gears. Therefore, a sudden breakdown of the gears could result in substantial financial losses. Due to this, extensive studies have focused on defect diagnosis. Both machinery maintenance decisions and preventive maintenance techniques have been aided by vibration analysis. An increased vibration is a warning sign that a machine is about to malfunction or break down. Observing and evaluating the machine's vibration pulses can identify the nature and extent of the issue and, as a result, predict when the machine will fail. The vibration signal may identify gearbox defects early on and diagnose its problems. Hence, this research highlights the main crucial steps that can be followed for defect detection and identification, mainly based on vibration analysis methodologies. It provides an application methodology for various signal-processing techniques used successfully in rotating machinery. The study briefly explains the applied methods to diagnose problems that depend on hybrid artificial intelligence approaches, such as fuzzy sets, expert systems, and neural networks. The key aspect of the present paper is the parametric comparison of the performance of various artificial Intelligence systems used in rotary machines. As such, the paper reports a comprehensive study of the gearbox defect diagnosis and provides useful analysis, which would be helpful for the usage of such techniques in the engineering industry.

This study presents a comprehensive numerical investigation into the energy evaluation and determination of dry moisture content of briquettes, a vital aspect of renewable energy production. Utilizing advanced computational fluid dynamics (CFD) modeling and simulations, we explored key parameters impacting briquette combustion, such as moisture content, size, density, and temperature profiles. The research demonstrates that these factors significantly influence combustion behavior, with the CFD model accurately predicting mass loss curves and burnout times. The process was completed in 10 minutes, reaching a temperature of 300K and yielding gases consisting of CO2, CO, and H2O, while the devolatilization front was assumed to be at 325K. The drying front was estimated to occur within the range of 303K to 310K. This knowledge is pivotal in optimizing briquettes as a sustainable energy source, ensuring efficient energy conversion, and reducing environmental impact. By integrating engineering principles, thermodynamics, and computational modeling, our interdisciplinary approach addresses complex challenges in renewable energy. The research findings underscore the importance of refining and validating these models to advance the understanding and utilization of briquettes as a clean and eco-friendly energy alternative. In a world increasingly prioritizing environmental sustainability and energy efficiency, this research aligns with broader efforts to transition towards cleaner and more sustainable energy sources, offering prospects for a greener and responsible energy future.

The climate change that the world is witnessing has cast a greater shadow on the Middle East. Iraq, one of the region's countries, is experiencing harsh thermal conditions. With the increase in population growth in the country, there was a significant development in the housing sector, which exacerbated the thermal loads that the residential sector requires to overcome harsh weather conditions. This leads to increased energy consumption. To reduce this consumption and energy waste, a simulation study was conducted using the TRNSYS program to analyze the thermal behavior of a building whose walls consist of Gypsum, Juss, brick, and mortar, as well as the roof consisting of Gypsum, Juss, and high-density concrete covered with sand and shtyger under weather conditions of Baghdad city with coordinates 33° N latitude and 44° E longitude, and to study the essential parameters such as building envelope, window-to-wall ratio (WWR), and internal sources that have a direct impact on the residential buildings. These parameters were processed and optimized to minimize the thermal loads annually. The results show that the optimal WWR is 25% in the south orientation. The annual thermal load can be reduced by about 49 % when covering the building envelope with a thermal insulation type (stone wall) with a thickness of 5 cm.

Resistance spot welding (RSW) is widely used in the automotive industry, particularly for copper-aluminum alloys in electric cars. RSW joint conductivity is crucial for electric vehicles. Welded parts may fracture due to tension, altering conductivity. The study examines resistance spot post-weld joint metallurgy and deformation-induced conductivity changes. The electric resistance of similar and dissimilar RSW joints was examined during tensile tests. Metallurgical tests for RSW joints revealed an increase in grain size from the base metal (BM) to the heat-affected zone (HAZ) and finally the fusion zone (FZ). Satisfactory shear tension strength results were obtained for dissimilar joints (Al-Cu) at 690 N and similar joints (Al-Al) at 780 N, exceeding the minimum limit of 643 N. However, weld strength in similar joints (Cu-Cu) only achieved 933 N, less than the required strength of 1528 N. Furthermore, the relationship between deformation rate (i.e., applied stress) and electrical resistance has been shown. It was found that resistivity increases with increasing deformation stress, resulting in decreased electrical conductivity with a high percentage, representing 99.8, 99.66, and 99.49% for Al-Cu, Al-Al, and Cu-Cu RSW joints, respectively. The electrical resistance was measured at the maximum force of 650 N and maximum stress of 33.1 MPa. The results show (15.7 Ώ, 5.9 Ώ, and 1.99 Ώ) and the electrical conductivities (0.063 IS, 0.169 IS, and 0.502 IS) for the joints (Al-Cu), (Al-Al), and (Cu-Cu), respectively.

Latent thermal energy storage systems are widely utilized to match the inequality between heat supply and demand. Despite these systems' wide range of uses in various applications, their high potential is limited by the slow charging rate. The target of this study is to augment the thermal performance of paraffin-based on triplex tube heat storage by dispersion of two different types of conductive mono nanoparticles (Al2O3, CuO) and hybrid Nano additives of various volume fractions (0.4, 0.8, 1.6, 3.2%) into paraffin wax. The experimental work involves measurements and preparation of the considered Nano-PCM. The enthalpy porosity model and finite volume method simulated the melting process. The study also investigated the temperature and liquid fraction variations in the axial, radial, and angular directions throughout melting to aid in predicting heat transfer in the storage throughout the phase transition process of PCM. Results revealed that including 1.6% of hybrid nanoparticles in PCM can increase the stored energy by 5.97%. The results also indicated that the hybrid nano-PCM exhibits the best phase transition rate and energy recovery for all volume fractions compared to mono-nano-PCM. At 1.6% volume fraction, the storage efficiency can be improved up to 76.8%, 75.5%, and 73.63% for hybrid nano-PCM, Al2O3-PCM, and CuO-PCM, respectively.

This paper investigates a novel study about the influence of airflow simulation of an air conditioner (AC) inlet angle impacting negative pressure control in an airborne isolation indoor room (AIIR). The study focuses on four cassette Air Conditioner units set at different angles (0, 15, and 30 degrees) and their effect on air quality and airborne contamination removal for respiratory patients and healthcare workers by using computational fluid dynamics (CFD) simulations. Carbone dioxide is used as a tracer gas. The results showed that at a 0-degree angle, higher CO2 concentrations were observed compared to inclinations of 15 and 30 degrees at three minutes. Inclinations of 15 and 30 degrees promote better air circulation with medium and high velocity, better Contaminant Removal Effectiveness (CRE), and better local Air Quality Index (LAQI), facilitating efficient dilution and dispersion of CO2. In addition, these angles reflect the direction of airborne contamination to the side of the wall and keep them away from the healthcare workers, ensuring the medical staff's safety. In conclusion, The LAQI findings indicated an index value of 1.01 when measured at a 15-degree AC angle. In contrast, measurements taken at 0 and 30 degrees yielded values of 0.96 and 0.93, respectively, and the coefficient of restitution (CRE) exhibited values of approximately 100, 99.8, and 98 for AC angles of 15, 0, and 30 degrees, respectively, under low AC -velocity conditions.