Babylonian Journal of Mechanical Engineering

Assessment of Changes in The Characteristics of Motor Oils in Grain Harvest Engines

2024-09-02T18:38:45+00:00

The period of use of grain harvesters is short and amounts to 1.5 – 3 months a year. The operating time of the internal combustion engine most often does not exceed 200 hours. At the same time, engines operate in harsh conditions of high temperatures, significant loads, and high dust levels in the air. As has been established, the engines of domestic combines and combines of the Republic of Belarus use M-10G2 and M-10DM motor oils.

Solar Air Heaters Classifications and Enhancement: A Review

2024-11-30T18:07:12+00:00

Solar air heaters (SAHs) are renewable energy systems that utilise solar radiation to heat air, offering sustainable solutions for space heating, agricultural drying, and industrial processes. These systems are simple in design, cost-effective, and environmentally friendly, making them essential to the renewable energy landscape. However, challenges such as low thermal efficiency, dependency on climatic conditions, and significant thermal losses limit their adoption. Recent advancements in design, materials, and operational strategies have significantly improved their performance. This review explores the principles of SAHs, innovations in design, thermal storage integration, and efficiency enhancement techniques. Applications in various sectors are discussed, highlighting ongoing research to maximise efficiency while maintaining economic viability and ecological benefits.

Numerical analysis of dual-fuel diesel engines in compression ignition engines: a review

2024-11-30T10:05:25+00:00

Hydrogen gas is currently used in many daily uses because of its chemical properties that help in combustion and energy generation processes. Hydrogen can be easily used in diesel engines without major design modifications. In additions, its high flame velocity and calorific value make it a desirable option for dual-fuel mode in diesel engines. The trend in developing car engines has become to use alternative fuels to diesel and gasoline. The types of injections currently used, their development technology in diesel engines, and the advantages of using them to develop and raise engine efficiency are discussed. A complete study is being conducted on the use of hydrogen as a dual fuel in diesel engines by changing the engine speed and the amount of hydrogen used in combustion, generating including energy and heat resulting from the use of hydrogen as a dual fuel. This study aims to determine the optimal conditions for using hydrogen as a dual fuel in diesel engines, taking into account both performance and environmental impact. The results of this research could potentially lead to more efficient and sustainable transportation options in the future. Furthermore, the study will also evaluate the emissions produced when using hydrogen as a dual fuel in diesel engines, to ensure that the environmental impact is minimized. By optimizing the use of hydrogen in combustion, this research has the potential to revolutionize the way we power vehicles and reduce our reliance on traditional fossil fuels.

Tubular Solar Stills: Review

2024-12-14T05:50:08+00:00

This study discusses tubular solar still concepts, designs, and performance improvement for sustainable water purification. A greener alternative to traditional methods, tubular solar stills use sun energy for evaporation and condensation. Advances in phase transition materials, reflectors, and nanotechnology improve heat efficiency and water output. The research shows their adaptability and ability to sustainably address global water scarcity in remote and disaster-affected areas. This study examines tubular solar still concepts, designs, and performance optimization for sustainable water purification. Tubular solar stills use sun energy for evaporation and condensation, a greener option. New technologies including phase change materials, reflectors, and nanotechnology boost heat efficiency and water production. Applications from distant to disaster-stricken locations show their versatility and capacity to sustainably manage global water constraint.

Numerical Investigation of Ribs Number Effect on Heat Transfer Inside A Heated Duct

2024-11-24T04:07:29+00:00

Numerical simulations of flow and heat transfer are conducted in a three-dimensional square duct, including circular ribs positioned at the mid-height. The properties of the rib are examined, including the rib count (1-2-5-7) and the placement angle (0, 30, 45 degrees). Reynolds number is set as constant at 5000 for all studied cases. The existence of these ribs significantly influences heat transfer. The heat transfer rate is directly related to the quantity of ribs and positioning angle. The maximum recorded enhancement in Nusselt number is 30%.

Active Techniques of Heat Transfer Enhancement: A review

2024-12-03T17:38:23+00:00

In this work, active methods for improving heat transfer are discussed, with a particular emphasis on new ideas and their applicability in various sectors of different types. Heat transfer efficiency is essential for optimising energy utilisation in industries such as chemical processing, heating, ventilation, air conditioning (HVAC), and renewable energy. Mechanical assistance, surface vibrations, electrostatic fields, and fluid injection are some approaches investigated in this research. The study also investigates the ideas behind these techniques and their practical ramifications. The results of this study indicate that active approaches, even though they often call for more power, have the potential to greatly improve thermal performance and provide new solutions for difficult technical difficulties.

Theoretical Investigation of The Major and Minor Losses in Pipes and Fittings

2024-11-22T17:09:23+00:00

The present study aims to investigate major pressure losses in pipes and minor losses in certain pipe fittings, such as sudden expansion. Initially, the relationships for calculating major and minor losses were derived by applying Bernoulli's equation to the studied components. Flow velocity, pipe diameter, and pipe length effects on major losses were examined. Additionally, the impact of velocity on minor losses in sudden expansion was analysed. The results demonstrated that major losses, represented by friction, significantly vary with changes in flow velocity, pipe diameter, and pipe length. It was found that increasing the pipe diameter by 200% leads to a 6% reduction in major losses. Moreover, increasing the length and velocity results in proportional increases in major losses. Regarding minor losses, the findings indicated that these losses in sudden expansion increase by a factor of six with the increase in velocity.

Effect of Inlet Velocity on The Entrance Length of Laminar and Turbulent Flow in A Circular Pipe

2024-12-03T03:50:20+00:00

This study uses numerical simulations performed with ANSYS-FLUENT to investigate the hydrodynamic entrance length for fluid flow in a circular pipe under both laminar and turbulent conditions. The effect of inlet velocity on entrance length and pressure drop was analysed. Two physical models with diameters of 15 cm and lengths of 10 m and 13 m were employed. The numerical results were validated against theoretical predictions, showing good agreement. The results indicate that entrance length increases with inlet velocity due to the extended development of the boundary layer. For laminar flow, entrance lengths of 1.46 m, 3.85 m, and 12.54 m were observed for velocities of 1, 3, and 10 m/s, respectively, while a turbulent flow velocity of 16.6 m/s yielded an entrance length of 5.8 m. Additionally, it was found that higher inlet velocities significantly amplify pressure drop due to increased friction and energy losses

Determination of Process Parameters For Removing Impurities from Motor Oils for Their Use as The Basis of Working and Preservation Fluids

2024-09-02T17:47:35+00:00

Motor oil that has spent a certain period of time in combined engines has a reserve of operational properties and can be considered as a basis for the preparation of working and conservation oil when storing equipment for a long period of storage [1].

Numerical Investigation of Grooved Obstacle on Heat Transfer Inside A Heated Duct

2024-11-30T14:51:55+00:00

Flow and heat transfer are simulated numerically in a 2-dimensional centerline- ribbed square duct for different values of the rib height to the duct height (Blocking ratio BR). The blocking ratio of these rectangular obstacles 0, 0.5 and 0.75 are examined. Three values of velocity (0.1, 1 and 4m/s) as inlet

working conditions were used. The top and bottom face of the duct are subjected to 1000 W/m2 heat flux. The heat transfer and flow structure with Ansys-Fluent inside a square duct in the presence of rotating vortex generators were studied and the influence of the blocking ratio (BR) on both heat transfer and fluid flow are examined. Numerical simulation was performed by using Ansys-Fluent 18. . In general, the enhancement raticon of heat transfer could reach 54%.

Exploring Passive Heat Transfer Enhancement Techniques: Applications, Benefits, and Challenges

2024-12-14T08:30:19+00:00

Techniques for enhancing passive heat transfer play a crucial role in boosting thermal performance in engineering systems without the need for external energy sources. These approaches, such as altering surface roughness, utilizing extended surfaces, incorporating porous media, and employing phase change materials, provide energy-efficient and economical solutions for a variety of uses, including automotive systems, HVAC, and cooling in electronics. This paper examines important passive techniques, focusing on their fundamental principles, real-world applications, and the challenges that come with them. The study highlights the importan*ce of sustainability and energy efficiency, showcasing how these approaches can meet contemporary thermal management challenges, even while facing issues such as material degradation and pressure drops in systems.

Examination of the parameters effect on Al-Cu FSW welded butt joints using formability consent

2024-11-29T14:50:11+00:00

In most applications, joining aluminum to copper using friction stir welding (FSW) is a primary manufacturing process followed by secondary forming processes. The aim of this study is to investigate the effect of FSW process parameters (speed and feed rate) on the formability of Al-Cu joints. Aluminum and copper blanks were welded at three different rotational speeds, i.e., 910, 1280, and 1700 rpm, and three different feed rates, i.e., 16, 29, and 44 mm/min. The base metals used in this study were aluminum (Al-1050) and copper in two states, i.e., as received and annealed. The mechanical properties of the base metals and the produced compounds were evaluated by tensile and hardness tests. The aluminum-copper joints were drawn into flangeless U-shape and cup shape using FSW to examine the formability of the joints. The maximum tensile load, punch load, and forming index were obtained when Al was at 1700 rpm and 16 mm/min, i.e., h. The welding was performed with annealed copper at the highest rotational speed and lowest feed rate due to work hardening of the joint. However, the ductility was highest at 1280 rpm and 44 mm/min, i.e., at medium rotation and highest travel speed. It can be depicted that when the FSW Al-Cu joint is further used in the forming process, moderate rotation and high feed speed should be adopted for welding to avoid work hardening and improve the ductility of the joint.

Types of Cooling Towers: A Review

2024-12-14T04:59:36+00:00

Cooling towers are indispensable in dissipating heat from industrial processes and HVAC systems, hence playing a significant role in operational efficiency and sustainability. This review describes the classification of cooling towers based on airflow mechanisms, methods of heat transfer, and applications. This study highlights recent developments in hybrid cooling systems that combine wet and dry cooling technologies for improved water conservation and thermal efficiency. Through the analysis of recent developments in the domain, this work describes innovative design considerations that optimize thermal performances by including environmental concerns; designs that are in the counterflow and crossflow configuration. These insights underline continuous improvements within cooling tower technologies in light of evolving industrial and ecological demands.

Review of the non-concentrating solar cookers with innovative absorber plates designs

2024-11-24T03:35:24+00:00

Preparation of meals has been named as one of the leading factors that affect the consumption of energy consumed globally as well as global emissions of greenhouse gases. Still due to these reasons that solar cooking is cheap and can be done at large scale, it is appropriate. To discuss the plan of cheap solar cookers, this paper gives an introduction of them, namely; box cooker with or without. In a free and natural way without panels, funnels or reflectors. Other designs that encompass virtually all kinds of the solar cooker also included are Fresnel, indirect, and parabolic-dish and parabolic-trough types. Scope is discussed further. Heat conservation tips, performance criteria, cost aspects, and improvement processes for heating systems design. This also brings into focus a high temperature 24 hour indoor solar cooker.

Heat Transfer Investigation Inside Heated Pipes of Different Cross-sections

2024-12-03T15:28:56+00:00

This research examines the thermal transfer efficiency in pipes including various cross-sectional geometries, such as circular, square, and triangular shapes. A computational fluid dynamics (CFD) methodology was used to model flow conditions and examine heat transfer and turbulence intensities under consistent boundary conditions. The results indicate substantial variations in thermal and flow characteristics across the geometries. Circular pipes provide greater convective heat transfer efficiency and minimum temperature gradients, but square and triangular pipes show more turbulence accompanied by a higher pressure drop. These insights may guide the design of efficient piping systems for many technical applications, including HVAC, chemical processing, and renewable energy systems.