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Introduction
Published in Krishnan Murugesan, Modeling and Simulation in Thermal and Fluids Engineering, 2023
In this textbook, energy conservation is focused only on thermal energy conservation, specifically heat energy conservation. In basic thermodynamics, it is known that energy can neither be created nor be destroyed. However, energy takes different forms using energy conversion devices. In the thermal engineering field of study, many systems involve energy transport in the form of heat. Work is also a form of energy in a thermodynamic sense. However, the conservation principle is stated only in general form as energy conservation. For example, in an internal combustion engine, fuel is burnt with air inside the cylinder, which gives rise to gases at high temperatures and pressures. These gases expand in the cylinder-piston arrangement to produce mechanical work as output (Figure 1.5(d)). When the overall energy conversion is considered in this example, one can appreciate that heat energy available in the fuel is converted into mechanical work. Of course, the same heat can be produced by burning coal or other fuels, and such engines are called external combustion engines. Now in the internal combustion engine, the total heat supplied by burning the fuel has to be accounted for in different forms. When part of the heat is available in the form of mechanical shaft work after overcoming friction in different machine components, some amount is rejected from the engine through exhaust gases; a fraction of the total heat is lost to the cooling water circuit used to cool the engine wall from overheating; and some heat is lost to the atmosphere through radiation and convection losses from the surface of the engine.
Magnetic dipole aspect of binary chemical reactive Cross nanofluid and heat transport over composite cylindrical panels
Published in Waves in Random and Complex Media, 2022
Syed Latif Shah, Assad Ayub, Sanaullah Dehraj, Hafiz A. Wahab, K. Martin Sagayam, Mohamed R. Ali, Rahma Sadat, Zulqurnain Sabir
Heat transfer has been extremely utilized in many diverse ranges of fields initiated from simple to complex loop-system. It is an arising fact whenever energy is required to be transformed or generated. Heat transfer is a branch of mechanical engineering generally and thermal engineering specifically related to the production and transformation of thermal energy between two systems. Heat transfer is further classified into different modes, namely, thermal conduction, convection, and thermal radiation. There are wide series of heat transfer industrial and non-industrial applications such as refrigerators, air conditions, solar water, heater, x-rays, and space heater [34], etc. Heat transport dissipative flows over a heated Riga plate with generalized differential quadrature analysis is made by Shah et al. [35]. Heat source/sink and heat transfer via convection in vertical cylinder is scrutinized by Wakif et al. [36]. Many scholars gave hue contribution in heat transport with radiative-reactive Walters-b fluid, porous medium in the presence of an adjustable heat source, radiative-convective motion of sodium, thermo-magneto-convection [37–41].
Cattaneo–Christov heat flux on MHD flow of hybrid nanofluid across stretched cylinder with radiations and Joule heating effects
Published in Waves in Random and Complex Media, 2022
Aamir Ali, Rukhsana Khatoon, Muhammad Ashraf, Muhammad Awais
Heat transfer is a subfield of thermal engineering that deals with the use, conversion, generation, and exchange of thermal energy between systems. There are several heat transfer mechanisms, including radiation, convection, and conduction. Heat transfer has numerous applications in climate engineering, chemical process industries, architecture, greenhouse effect, and human body heat transfer. Temperature gradients have a large influence on fluid properties. Temperature and viscosity, in particular, have a direct relationship in gases, whereas temperature and viscosity have an inverse relationship in liquids. Radiation is a method or mode of transferring energy from one medium to another without the use of a third medium. Radiation from radioactive elements is emitted in all directions and travels to the point of absorption. Radiation can take the form of waves or particles. Heat is particularly transferred in vacuum through radiation in the form of electromagnetic waves because these waves can be transferred without the use of any medium, namely space. Rehman and Shatanawi [45] studied the flow of Jeffrey fluid over an inclined surface with nonlinear thermal radiation, MHD, and heat flux effects. They use the shooting method to solve the problem numerically. Rehman et al. [46] presented a numerical comparison of stagnation point flow with the influence of chemical reaction, thermal radiations, stagnation point, and heat flux on the flow of Jeffrey fluid over an inclined stretched surface. Similarly, Rehman et al. [47] presented the effects of these properties for viscous fluid over a linear twisting cylinder. They present the numerical solution using the BVP-Midrch routine, which is included with the Maple software. The heat produced by the flow of an electric current through a conductor is referred to as Joule heating. Joule heating is used in a variety of everyday applications, such as electrical fuses, glowing filament of an incandescent light bulb, electrical tabletop hotplates, and so on. The effects of convection, radiation, and Joule heating for Newtonian and non-Newtonian fluid across a stretched cylinder have been studied by researchers [48–59]. Velocity slip effects, thermal radiation, and temperature convective boundary conditions will all be considered. Imtiaz et al. [60] investigated convective heat mass transport in a mixed convection flow with nanoparticles in the boundary layer. They discovered that as the Hartman number rises, so does the flow of fluid. Sayed et al. [61] investigated the peristaltic process for two separate nanofluid particles in a non-Newtonian fluid with convective boundary conditions along an inclined channel. They conclude that copper and aluminum oxide nanoparticles had a substantial impact on heat transfer coefficients and the axial velocity field.