Journal of Advanced Research in Fluid Mechanics and Thermal Sciences

Experimental Investigation on the Aerodynamic Parameters of Trailing Edge Wake Generators

Mohamed Ibren, Waqar Asrar, Muhammad Ariffuddin Ismail, Amelda Dianne Andan — Mon, 15 Apr 2024 00:00:00 +0000

In the realm of aerodynamics, the investigation of airfoil performance stands as a critical domain, with an ever-growing emphasis on optimizing designs for enhanced efficiency. This study investigates the aerodynamic performance of a NACA 0015 airfoil featuring various trailing edges, including serration, comb, poro-serration, and comb-serration. The experiments were conducted in a wind tunnel at angles of attack ranging from -15° to 15° and Reynolds numbers of 1.5 x 10⁵ and 2.0 x 10⁵. To accurately quantify the forces and moments acting on the airfoil models, a calibrated six-component balance was utilized to measure the aerodynamic coefficients of each airfoil configuration. The lift coefficient (c_l), drag coefficient (c_d), and pitching moment coefficient (c_m) are analyzed for the various trailing edge types and Reynolds numbers. Results indicate that the baseline model demonstrated better aerodynamic performance compared to other types of trailing edge. Most trailing edges, except the baseline, resulted in a decrease in the lift coefficient. However, at very low angles of attack, the airfoil showed an improvement in the maximum lift coefficient. Most trailing edges exhibited an increase in the drag coefficient at a Reynolds number of 1.5 x 10⁵. However, at a Reynolds number of 2.0 x 10⁵, the drag coefficient showed a similar trend as the baseline. All types of trailing edges, including the baseline, displayed a similar trend in the pitching moment coefficient. When evaluating the lift coefficient to drag coefficient ratio, all trailing edges generally performed similarly at all Reynolds numbers. In general, the baseline model emerges as the optimal choice, showcasing superior aerodynamic characteristics across the evaluated parameters.

Thermoacoustic Cooler with Different Waveform Excitations and the Noise Control Test

Mon, 15 Apr 2024 00:00:00 +0000

Many researchers have been devoted into improving the operation of thermoacoustic cooling system as it offers a promising alternative to traditional cooling methods. This study reported potential system’s improvements that can be obtained when it is operated with different excitation of waveforms and resonator’s material. Resonant test was first carried out to identify the frequency for the operation. Temperature drop that can be obtained by the system was then tested for sine wave, square wave and triangle wave excitations. It was found that a change in resonator material alters the resonance frequency for the operation. Resonance was recorded at 186.6 Hz when acrylic resonator was used while a resonance frequency of 170.5 Hz was found when polyvinyl-chloride’s resonator was used. In term of temperature effects, the square wave excitation resulted to the maximum temperature difference of 45.64˚°C in the acrylic resonator, followed by sine wave at 43.46°C and triangle wave came in last at 40.11°C. Then, as the polyvinyl-chloride’s resonator was used, smaller values of maximum temperature was observed with 38.07°C, 35.94°C and 30.05°C for square wave, sine wave and triangle wave, respectively.

Investigation of the Effect of Different Fins Configurations on the Thermal Performance of the Radiator

Mon, 15 Apr 2024 00:00:00 +0000

Fins play a crucial role in enhancing heat transfer in various engineering and industrial applications. In this paper, the significance of fins in heat transfer as well as the design of radiators for thermal management are discussed. Fins increase the surface area and improve convective heat transfer. Fins, however, may decrease the surface area available for heat exchange and raise airflow resistance. In order to maximize thermal performance, this study emphasizes the necessity of having a thorough understanding of the relationship between fins and tubes in radiator design. The objectives of the research are to maximize surface area for heat dissipation, assess the impact of fins on heat transfer efficiency, and examine their functions. Thermal performances of radiators with various fin densities that is, radiators with six, eight, and ten fins per inch (FPI) have been investigated using Computational Fluid Dynamics (CFD) Analysis. The ten FPI configurations, in particular, showed remarkable thermal performance, indicating its potential for applications requiring strict thermal control. Further, it is also revealed that the outlet temperature dropped as the FPI rose and proved that the FPI and outlet temperature have an inverse relationship. These findings serve as a foundational framework for future research projects and practical applications, providing essential insights into designing more effective and efficient cooling systems.

An Experimental Study of the Transfer of Heat in Nanofluid of a Tiny-Channel using Several Innovative Arrangement Designs

Ameer Abed Jaddoa, Mahmoud Mustafa Mahdi, Hussain Saad Abd, Jafaar Mohamme Daif — Mon, 15 Apr 2024 00:00:00 +0000

This work presents an experimental investigation of the heat transfer (HT) and pressure drop characteristics associated with three different configuration models of minichannel heat sinks. This study utilizes a coolant consisting of TiO₂ nanoparticles dispersed in water at a weight concentration of 10%. The performance of this nanofluid coolant is then evaluated and compared to that of distilled water under several heating powers ranging from 100 to 300 W. The findings suggest that the thermal performance of TiO₂ nanofluid is significantly influenced by heating power (HP), and its HT efficiency can be enhanced more efficiently at lower levels of HP. However, it has been observed that when the HP decreases, the pressure drop increases. This effect is more pronounced in TiO₂ nanofluid than in pure water, which can be attributed to the difference in viscosity with temperature. The Nusselt number remains constant regardless of the increase or reduction in HP. Consequently, when pure water is utilized, the experimental Nusselt number aligns with the Peng and Peterson empirical correlation for all HPs, with an accuracy of 15%. The TiO₂ nanofluid was used to test the lowest wall temperature, 40 °C. This measurement was obtained at a Reynolds number of 1100, equivalent to a heat power (HP) of 100 W. Furthermore, it is noted that when the fluid passes through the mini channel, there is an increase in the axial temperature from the input to the outlet of the heat sink (HS). The maximum enhancement observed for a power input of 100 W is 19.59% when utilizing configuration A. This is attributed to the combination of a weak buoyancy force and an increase in the surface area of HT. The HP highly influences the system's thermal performance, and its effective HT characteristics are more pronounced at lower HP levels.

Eyring-Powell Fluid Flow Past a Shrinking Sheet: Effect of Magnetohydrodynamic (MHD) and Joule Heating

Iskandar Waini, Anuar Ishak, Ioan Pop — Mon, 15 Apr 2024 00:00:00 +0000

This paper examines the effect of magnetohydrodynamic (MHD) on Eyring-Powell fluid flow over a shrinking sheet. The sheet is permeable and it is shrunk with power-law velocity. By employing the suitable similarity transformations, the governing equations are transformed into the similarity equations, and MATLAB software is used to program the code with the aid of the bvp4c function. Results reveal that the magnetic and the suction parameters raise both the velocity and temperature gradients, which consequently increases the skin friction and the heat transfer coefficients. However, these physical quantities are reduced with the Eyring-Powell fluid parameter. The domain of the solutions is affected by the rise of the magnetic and the Eyring-Powell fluid parameters. From the stability analysis, the second solution is unstable while the first solution is stable over time.

A Numerical Investigation of the MHD Ternary Hybrid Nanofluid (Cu-Al2O3-TiO2/H2O) Past a Vertically Stretching Cylinder in a Porous Medium with Thermal Stratification

Rupam Shankar Nath, Rudra Kanta Deka — Mon, 15 Apr 2024 00:00:00 +0000

This study focuses on examining the impact of thermal stratification on the magnetohydrodynamics (MHD) flow of water-based nano, hybrid, and ternary hybrid nanofluids past a vertically stretching cylinder in a porous medium. The nanoparticles Cu, Al₂O₃, and TiO₂ are suspended in a base fluid H₂O, leading to the formation of a ternary hybrid nanofluid Cu-Al₂O₃-TiO₂ /H₂O. The numerical results are calculated with the 3-stage Lobatto IIIa approach, specifically implemented by Bvp4c in MATLAB. The impacts of various parameters are visually depicted through graphs and quantitatively represented in tables. The velocity and temperature of the ternary hybrid nanofluid are lowered by the thermal stratification parameter compared to when there is no stratification. The ternary hybrid nanofluid has a higher heat transfer rate than the hybrid nanofluid, and the hybrid nanofluid has a higher heat transfer rate than ordinary nanofluids.

Squeezing MHD Flow of Sodium Alginate-Based Casson Hybrid Nanofluid with Soret and Dufour Effects

Mon, 15 Apr 2024 00:00:00 +0000

Ultrahigh-performance cooling is one of the essential requirements in the industrial technology. Hence, the new heat transfer fluid, hybrid nanofluid is introduced to increase the thermal conductivity of fluid and investigated with various physical parameters. The unsteady magnetohydrodynamics (MHD) flow of Casson hybrid nanofluid through two surfaces in a permeable medium with chemical reaction are explored. The hybrid nanoparticles of Alumina and Copper is dispersed in the base fluid of sodium alginate . The discretize equations are solved using similarity transformation and Keller-box methods. The comparison of the current results with the published results for validation is conducted and discovered in proper agreement. The impacts of squeeze, magnetic, porous media, chemical reaction, heat sink/source, and Soret and Dufour on behaviour and physical quantities of flow are discussed. The graphical results show the squeeze of two surfaces accelerates the fluid velocity near the upper plate region. Further, the velocity slowing down when and increases, and it elevates as and rises in the middle of channel. The increment of heat transfer rate and temperature of fluid is shown for increasing E_c, y and Du, and the opposite behaviour is discovered with raise in. The fluid concentration decreases and the mass transfer rate enhances for rising Sr. The concentration enhance and rate of mass transfer reduce with the constructive chemical reaction, whereas contrary effects is shown for destructive chemical reaction.

Exploring the Impact of Diverse Cooling Duct Configurations on Photovoltaic Panel Performance

Mohammad N. Alqahtani, Hashem F. Shatnawi — Mon, 15 Apr 2024 00:00:00 +0000

Photovoltaic (PV) panels are an emerging technology that captures solar energy and produces electricity. One key concern with PV panels is the detrimental effect of high temperatures on their performance and efficiency, which is leading to a shorter service life. Cooling the panels can help to maintain appropriate working temperatures, reduce the adverse effects of heat, and increase overall energy production. This research aims to investigate experimentally and numerically the effectiveness of a cooling channel with different configurations in lowering PV panels' temperature. The findings of the experiments show that cooling methods improved panel efficiency by 0.35% and reduced the intake temperature by 7%. In numerical analysis, different 3D cooling channel geometries were investigated, and the tapered duct was found to be the best in reducing Tav at 1.73%.

Water-in-Biodiesel Emulsion with Hydroxy (HHO) Gas Fuel Enrichment for Single-Cylinder Diesel Engine Application

Mon, 15 Apr 2024 00:00:00 +0000

The rising issue of the depletion of fossil fuels opened a new pathway to seek alternative fuels to fulfil World Sustainable Development Goals (SDG). The application of high-blending biodiesel is possible however, it causes the diesel engine to perform poorly due to high viscosity, high fuel consumption, and increased NOx emission. To comply with the strict regulation, the idea of combining alternative fuels of high blending biodiesel, water-in-biodiesel emulsion, and hydrogen is seen as possible to solve the issue of each alternative fuel. Therefore, this study focused on the effect of high blending of biodiesel, water-in-biodiesel emulsion with hydroxy (HHO) enrichment in single-cylinder diesel engines on engine performance and exhaust emission. The fuel tested for this study are B10, B50, and an emulsion of B50 with the addition of HHO known as B50H and tested on engine speeds of 2400rpm under various loading conditions of 1kW, 2kW, 3kW, and 4kW. The result showed the B50H showed improvement in Fuel Consumption (FC) by 4%, 5% for Brake Thermal Efficiency (BTE), and reduced Nitrogen oxide (NOx) by 23% compared to B10 fuel. Thus, the combination of high blending of biodiesel, water-in-biodiesel emulsion, and HHO gas successfully improved diesel engine performance and reduced harmful exhaust emissions to promote clean and renewable energy, without depending on current diesel fuel.

The Influence of Window-to-Wall Ratio (WWR) on Airflow Profile for Improved Indoor Air Quality (IAQ) in a Naturally-Ventilated Workshop in a Hot-Humid Climate

Mon, 15 Apr 2024 00:00:00 +0000

Indoor air quality (IAQ) has become a major concern worldwide as indoor air pollution rapidly becomes a public health issue. IAQ plays a pivotal role in occupants' health and comfort and influences their productivity and work efficiency. Many studies have been done on IAQ of common building spaces such as offices, residential buildings, and educational institutions, but the availability of IAQ studies on workshops is limited, considering the significant implications for workers' health and performance. Thus, this paper aims to study the effectiveness of natural ventilation in a workshop based on the influence of different window-to-wall ratios (WWR). Electronic databases are utilized to obtain data, and the findings collected are categorized based on research methodology, issues, and findings. The air movement as part of the physical parameters of IAQ is studied through the application of Computational Fluid Dynamic (CFD) simulation to observe and analyse the airflow pattern and the air velocity of the naturally ventilated workshop with different WWRs. The research outcome underscores the ideal WWR for effective natural ventilation in a workshop is 0.30. However, the study observes that the effectiveness decreases as WWR exceeds 0.50. Further research on the openings' location, inlet, and outlet sizes and application of mechanical ventilation can be conducted to improve the measurement of the IAQ effectiveness in a naturally ventilated workshop.

Study to Establish the Relationship Between Fuel Injection Parameters and Exhaust Emission Content of Fishing Vessels’ Diesel Engines to Diagnose the Technical State

Mai Duc Nghia, Ho Duc Tuan — Mon, 15 Apr 2024 00:00:00 +0000

Fuel injection parameters of diesel engines are essential. It directly affects the process of forming the combustion mixture, fuel combustion, and emission formation. The fuel injection pressure with the pressure at the end of the compression stroke in the engine cylinder at the time of fuel injection is worth noting. If the above parameters are reduced compared to the technical requirements, the combustion process is incomplete, and soot emissions increase. On that basis, the article studies the relationship between fuel injection parameters and exhaust emissions by simulation and experimental methods, through which it is possible to recognize emission results for the diagnosis technical state of the fuel injection system and the group that encloses the engine’s combustion chamber. Research results on the 6CHE Yanmar diesel engines of the fishing vessels at zero load conditions show that. When soot emissions increase by more than 20%, the fuel injection pressure is reduced compared with technical requirements. The fuel injection system and the group that encloses the combustion chamber need to be maintained on time to prevent damage incidents that may occur and to ensure the safety of people and fishing vessels when operating at sea for a long time.

Experimental Study of Hybrid Photovoltaic (PV/T) Thermal Solar Collector with Air Cooling for Domestic Use: A Thermal and Electrical Performances Evaluation

Saadi Zine, Boukhlef Djedjiga, Salem Fethya, Lachtar Salah, Bouraoui Ahmed — Mon, 15 Apr 2024 00:00:00 +0000

Photovoltaic-thermal (PV/T) collectors convert solar energy into both electrical and thermal energy. This conversion enables the cooling of solar cells while also allowing the produced thermal energy to be used to heat water or space. A hybrid solar panel converts the heat emitted by photovoltaic cells into a transfer fluid (liquid or air), enhancing PV cell efficiency while also producing useful solar heat for household hot water or heating. The heated air extracted from the PV/T collector can be used as a heat source for the building. The paper presents a baffle-based collector for a photovoltaic/thermal system (PVT) to increase output from the system using solar power by comparison with a PVT system without baffles, and its electrical and thermal performance are analysed with the experimental results. Baffles are a solution for optimizing the performance of flat plate solar collectors, which often have low performance. Three typical days from the March 2022 season were chosen and presented as part of this study. For the experiments, two fans were used for air extraction in the PV/T collector, with three speeds chosen: 0.02804 m³/s, 0.0082 m³/s, and 0.016 m³/s, respectively. The variation in thermal and electrical efficiencies of PV/T solar collectors has been calculated for the three tests of March 3, 4, and 5, 2022. The results indicated that the thermal and electrical efficiencies of the PV/T collector were on average 86% and about 9%, respectively, and the thermal efficiency improved by 22% compared with a PV/T collector without baffles in the absorber.

Magneto Hydrodynamic Effects on Unsteady Free Convection Casson Fluid Flow Past on Parabolic Accelerated Vertical Plate with Thermal Diffusion

Ganesan Radha, Ayothi Selvaraj, Soundararajan Bhavani, Periasamy Selvaraju — Mon, 15 Apr 2024 00:00:00 +0000

The free convection MHD flow of a viscous, chemically reactive, electrically conducted, incompressible, and Casson fluid past a parabolically accelerated vertical plate was examined in the present article along with the transfer of the heat & mass in the incidence of thermal radiation. The inverse Laplace method is used to resolve the dimensionless equations. The concentration and temperature fields, axial and transverse velocity are examined for distinct parameters like the (Casson fluid), Sc (Schmidt number), Gr (thermal Grashof number), Pr (Prandtl number), and Gm (mass Grashof number). Utilizing the temperature of fluid and concentration of species as a solution is also proposed. Graphical representations of the fluctuations in temperature of fluid and velocity along species concentration are provided for several values of relevant flow parameters.

Suggestion of Correlations to Obtain Shell and Tube Side Nusselt Numbers in Coiled Heat Exchangers

Magar Susheel Madhavrao, Gugliani Gaurav Kumar, Navthar Ravindra Rambhau — Mon, 15 Apr 2024 00:00:00 +0000

In coiled tube heat exchangers increase in curvature ratio and effective contact of shell fluid with coil surface led to better thermal characteristics. This work addresses study of thermal performance, shell and tube heat transfer coefficients (h_o and h_i). Also, mathematical correlations are predicted to obtain shell and tube Nusselt numbers (Nu_o and Nu_i). In the designing of compact coiled heat exchangers consisting of straight helical coil (SHC), conical coil (CC) and spiral coil knowledge of Nu_o and Nu_iis necessary whereas mathematical correlation to calculate Nu_o considering variations in shell geometry is not found. Five heat exchangers consisting of three cone coils (angle, ϴ = 30°, 50° and 70°), spiral coil (ϴ = 0°) and SHC (ϴ = 90°) are tested. Using Wilson plot method h_oand h_i are obtained for wide range of tube side Reynolds numbers (Re_i = 3700 - 21000). It is observed that, highest h_ois obtained for ϴ = 30°CC with better thermal performance. Lowest h_ois obtained for ϴ = 90°SHC. Ratio of height of shell, H_s and diameter of shell, D_so is considered in prediction of single correlation as: Nu_o = 16.55.Re_o^0.55.Pr_o^0.4 *(H_s/D_so)^0.096. Comparison with experimental findings shows variation of 0-14%. Similarly two correlations are proposed as: Nu_i = 0.0512.Re_i^0.80.Pr_i^0.4.CR_ave^0.18 and Nu_i = 0.0365.De_i^0.815.Pr_i^0.4.CR_ave^-0.3. A fair agreement is found with existing researchers.

Investigation of Thermal Similarity and Performances of Solar Thermal Air Collector with Heat-Soaked Vehicle Cabin

Adel Abulgasm Lahimer, Amir Abdul Razak, Kamaruzzaman Sopian — Mon, 15 Apr 2024 00:00:00 +0000

This article explores the potential of vehicle interiors, which can reach temperatures of up to 120°C due to solar exposure, as efficient solar collectors. Comparative studies have been conducted on the thermal behavior of heat-soaked vehicle cabins and dedicated solar collectors, highlighting their potential benefits in heating, cooling and ventilation. Thermal soak tests reveal a remarkable similarity in thermal performance between the two, with minor temperature variations of up to 5.3°C between the equivalent components. These temperature deviations are mainly due to differences in absorptivity characteristics, in which the black absorber plate exhibits superior absorption capabilities compared to the grey interior cabin surfaces. Integration of ambient air through the inlets on the cabin floor helps with initial cooling of the hot soaked cabin. The collector benefits from a preheated air mixture (comprising heat-soaked cabin air and ambient air), which improves its operating temperatures. This characteristic is attributed to the synergistic integration of the two systems. By decoupling these systems and aligning the properties of the absorber plate, the cabin and the collector could become thermally identical. The potential of the heated vehicle cabin as a power generation source is underscored, which presents opportunities to supplement the energy demand in remote locations. This study illuminates the untapped potential of vehicular solar heat capture, highlighting its feasibility, diverse applications, and significant implications for sustainable energy strategies and community development.