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We have used Bayesian Regularization Back Propagation based deep neural networks to analyze the flow and heat transfer behavior for the flow of a nanofluid (aluminum-oxide in kerosene oil) within a regenerative cooling channel in a rocket engine. The significance of this research lies in its contribution to the advancement of aerospace engineering by addressing the complex flow dynamics of nanofluids in rocket propulsion systems. The aim of this study is to analyze the behavior of a mixture of kerosene oil and aggregated/non-aggregated aluminum oxide nanoparticles, considering thermal radiation and viscous dissipation effects. The research methodology involves transforming primary equations into a dimensionless form using a similarity transformation technique and employing the bvp4c numerical computation method in MATLAB. The ANN-IBR method is trained, tested, and validated using reference datasets obtained from numerical computations to approximate flow solutions under various scenarios with different physical parameters. The conclusion of this study indicates that the proposed ANN-IBR model effectively addresses the flow of kerosene and nanoparticles within the rocket engine, demonstrating its accuracy through comparison with reference outcomes based on mean square error analysis, transition states examination, histograms analysis, and regression analysis. This research provides valuable insights for aerospace engineers to enhance the design efficiency of regenerative cooling systems in liquid rocket engines. [ABSTRACT FROM AUTHOR]

Active and passive cooling are the two possible methods for removing heat. An active cooling system is the one that involves the use of energy as opposed to passive cooling that uses no energy. Passive cooling methods are cost effective and more reliable than active cooling due to the absence of moving parts. Microchannel heat sink is one of high-tech devices that have widely considered passive cooling methods especially for electronics cooling. In this paper, the use of passive cooling methods in microchannel heat sink is comprehensively discussed. This paper also present the effects of some important parameters such as the type of channel types, surface roughness, fluid additives, and Reynolds number on the rate of heat transfer in microchannel heat sink. Finally, the conclusions and important summaries were presented according to the data collected. [ABSTRACT FROM AUTHOR]

Carbon nanotube (CNT) has the highest thermal conductivity among the nanoparticles that were discovered so far. Attempts to utilize them as heat transfer fluids by dispersing them into any kinds of base fluids called CNT nanofluids have been thoroughly conducted. However, one of the challenges faced by many researchers in applying their prepared CNT nanofluids is to maintain its homogeneous state and long-term stability. This paper presents an inclusive review on the preparation techniques and the reported period of stability of stationary CNT nanofluids. The characteristics of available treatment such as chemical treatment (covalent and non-covalent) and physical treatment methods have been systematically analyzed. Finally, the challenges and future trends of CNT nanofluids are discussed. [ABSTRACT FROM AUTHOR]

The laminar time-dependent fluid flow of an engine oil (Zinc Oxide−Society of Automotive Engineers 50 alias ZnO − SAE 50 nano-lubricant) through a rectangular channel is presented. The channel is made up of permeable walls that can expand or contract. It is also under the impact of thermal radiation and magnetic field is dominant enough to be ignored. The lower and upper walls of the channel bear different permeabilities and temperatures. Hence, a system of governing nonlinear partial differential equations is setup by means of conversation laws and aforementioned assumptions. By the implementation of suitable similarity transformations and conservation of mass, the equations for momentum, and energy are reduced to relatively simpler system of ordinary differential equations. The resulting system is solved by employing a semi analytical technique named as Subdomain Method (SDM). The results are further supported by another numerical scheme (a duos of shooting method along with Runge-Kutta-Fehlberg algorithm). The functioning of flow and temperature profiles under the variation in significant physical parameters is demonstrate upon the description of graphs and tables. Thorough discussions and concluding results are also presented at the end of the manuscript. • The flow of ZnO-SAE50 nanolubricant inside a rectangular channel with expanding and contacting permeable walls is considered. • Nanoparticles volume fraction affects the flow and temperature profiles. • The rate of heat transfer at the walls is affected by imposed thermal radiation and the presence of magnetic field. • Subdomain Method can be used to solve problems related to the flows inside expanding contacting channels. • The flow is only due to suction or injection. [ABSTRACT FROM AUTHOR]

Nanofluids have gained significant attention in recent years due their great potential for heat transfer enhancement . The heat transfer of nanofluids can be numerically studied using a single-phase or two-phase approaches. The first assumes that the fluid phase and nanoparticles are in thermal equilibrium and move with the same velocity, while the second requires more computational effort but provides the possibility of understanding the behavior of both fluid phase and solid particles in the heat transfer mechanism. This paper reviews various computational approaches to predict fluid flow and heat transfer characteristics of nanofluids. The characteristics of single-phase and two-phase (volume of fluid, mixture, Eulerian–Lagrangian and Eulerian–Eulerian) approaches have been analyzed and discussed systematically. Latest development and recent researches related to the computational nanofluids are also given. [ABSTRACT FROM AUTHOR]

This paper reviewed the application of nanofluids in vehicle engine cooling system. So far, nanoparticles have been used in engine oil, transmission oil, and radiator coolant to enhance heat transfer removal from vehicle engine. The heat transfer performance of nanofluids has been reported to perform better compared to pure fluid. This review focused on the experimental and numerical studies by previous researchers and their suggested amount of nanoparticles for optimum performance in vehicle engine cooling system. Finally, the conclusions and important summaries were presented according to the data collected. [ABSTRACT FROM AUTHOR]

The solids have higher heat transfer rate comparative to fluids, thus, in the present article, two different ferrite nano-particles are suspended in two different base fluids to demonstrates its impacts on the friction drag and heat transfer. Ferrites nano-particles are used because of the existence of Curie temperature in these particles, a property that makes them distinct from other nano-particles. Distinct ferrites have different Curie temperature, this means that the presence of ferrite nano-particles in base fluids makes them efficient for heat transfer in ferromagnetic fluid flows. Thus, this article focuses to study two ferrites, i.e., Magnetite ferrite Fe 3 O 4 and Manganese zinc ferrite MnZnFe 2 O 4 with base fluids water H 2 O and refrigerant-134A C 2 H 2 F 4. Heat transfer and friction drag are carried out for these hybridized ferrites nanoparticles in ferromagnetic nano-fluids. The higher velocity field is seen for the hybrid nanofluid MnZnFe 2 O 4 -Fe 3 O 4 -H 2 O-C 2 H 2 F 4 , whereas, the lowest velocity field is demonstrated for the nanofluid Fe 3 O 4 -H 2 O. [ABSTRACT FROM AUTHOR]

During the past decades, the technology to make particles in nanometer dimensions has been improved and a new kind of solid–liquid mixture, which is called a nanofluid, has appeared. Nanofluids are an advanced kind of fluid containing a small quantity of nanoparticles (usually less than 100 nm) that are uniformly and stably suspended in the liquid. The dispersion of a small amount of solid nanoparticles in conventional fluids such as water or ethylene glycol changes their thermal conductivity remarkably. Since then, nanofluids have been applied to enhance the thermal performance of many engineering systems. Recently, nanofluids have been used as heat transfer fluids to enhance the performance of solar collector devices. This paper reviews the recent progress and applications of nanofluids in flat-plate and evacuated tube solar collectors. Other than to review the efficiency of solar collectors with nanofluids, the paper also discusses the impact of nanofluids in solar collectors on economic and environmental viewpoints. Finally, the challenges and future trends in the application of nanofluids in thermal solar collectors are discussed. [ABSTRACT FROM AUTHOR]

In this article, turbulent flow characteristic of nanofluids is thoroughly reviewed. Turbulent flows have unique characteristics and are preferred in many industrial applications. Therefore, this paper reviews different techniques used to enhance heat transfer using nanofluids within turbulent regime. This paper also presents the effects of some important parameters such as nanoparticle type, nanoparticles concentration, and Reynolds number on heat transfer rate. Studies on numerical techniques are also discussed. Finally, the conclusions and important summaries are presented according to the data collected. [ABSTRACT FROM AUTHOR]

This article deals with numerical analysis of two-dimensional viscous fluid in modified square duct. A rectangular obstacle with constant temperature at walls is placed inside it. Flow duct is depicted in Figs. 1 and 2. Influence of Prandtl number and geometry on heat transfer of working fluid is studied in two cases. Computation for the present model is made in commercial package ANSYS-Fluent. Calculations are carried at two different values of Reynolds numbers i.e., Re 40 and 200 for each of the cases. Liquid water (H 2 0) and Liquid Aniline (C 6 H 5 NH 2) are taken as working fluids. Stream functions, isotherms, vorticity, velocity and pressure profiles are examined. Graphical data for C f and Nu is presented to analyze the effect of Reynolds number and Prandtl number on heat transfer. Thermal boundary layers are discussed in each of the cases. It is shown that heat transfer has high dependance on Reynolds number and Prandtl number. Geometry of the problem has noticeable effect on heat transfer. [ABSTRACT FROM AUTHOR]