Evolution of Designs for Constructal Cooling of a Square Plate Using Water, Ionic Liquid, and Nano-Enhanced Ionic Liquids

Author(s):  
Ashok K. Barik ◽  
Swetapadma Rout ◽  
Pandaba Patro

Abstract In this paper, we investigate the design-evolution of an embedded pipe based on the constructal theory to obtain the best design that cools a square plate subjected to a constant heat flux boundary condition. The water, ionic liquids (ILs), and nano-enhanced ionic liquids (NEILs, i.e., [C4mim][NTf2] + Al2O3 and [C4mpyrr][NTf2] + Al2O3) have been used as the coolants. Several designs (Case 1 to Case 11) have been tested to quantify the non-dimensional temperature of the heated substrate by implementing the finite volume method of ansys fluent. The three-dimensional continuity, momentum, and energy equations have been solved iteratively in the fluid region by incorporating SIMPLE algorithm with appropriate boundary conditions; while the conduction equation is solved in the solid region. Among all the considered designs, it has been found that Case 3 provides a better cooling effect for the heated substrate. For all of the considered configurations/designs, it is also found that the non-dimensional temperature decreases with the length of the morphing pipe. NEILs exhibit a better cooling effect of the substrate when compared with the ILs and water. The present numerical methodology is also validated with the previous literature.

Author(s):  
Yujie Qiu ◽  
Xiangkai Meng ◽  
Yangyang Liang ◽  
Xudong Peng

A three-dimensional thermohydrodynamic (THD) model of a notched mechanical seal is developed based on the commercial software ANSYS Fluent. The flow behavior of hot and cold fluid in and around the notch, namely, the thermal mixing effect, is detailly analyzed. The heat transfer between the notch fluid and the seal rings as well as the cooling effect mechanism of the notch are discussed. Finally, a parametric analysis is conducted to study the effect of notch size, rotational speed and seal gap on heat transport. The results show that the notch fluid locally decreases the notched stator face temperature around the notch boundaries. The reflux occurs between the sealing chamber and notch, which brings the most cooling effect to the notch. The notch depth and width have a significant effect on the heat transfer between the fluid and sealing rings. Because of the non-simplified THD model, the proposed research provides increased reliability of understanding the flow and temperature behavior in the notch.


2021 ◽  
Vol 132 (2) ◽  
pp. 302-312
Author(s):  
A. A. Gavrilina ◽  
L. Yu. Barash

Abstract We study unsteady internal flows in a sessile droplet of capillary size evaporating in constant contact line mode on a heated substrate. Three-dimensional simulations of internal flows in evaporating droplets of ethanol and silicone oil have been carried out. For describing the Marangoni flows we find it necessary to account for the diffusion of vapor in air, the thermal conduction in all three phases and thermal radiation. The equations have been solved numerically by finite element method using ANSYS Fluent. As a result of the simulations, the nonstationary behavior of Bénard-Marangoni (BM) instabilities is obtained. At the first stage, a flower structure of BM cells near the triple line emerge. For smaller contact angles, the cells grow in size and occupy the central region of the droplet surface. Being closely connected with recent experimental and theoretical studies, the results obtained help to analyze and resolve the associated issues.


2017 ◽  
Vol 139 (10) ◽  
Author(s):  
Yahya Sheikhnejad ◽  
Mir Mehrdad Hosseini ◽  
Antonio Teixeira ◽  
Ali Shahpari ◽  
Reza Hosseini ◽  
...  

This study includes experimental and three-dimensional numerical analysis of conjugate steady-state laminar forced ferroconvection of Newtonian incompressible ferrofluid through a horizontal circular pipe under constant heat flux and in presence of transverse magnetic field. The magnetic field was applied by two fixed parallel magnet bars at the beginning of the tube. To validate the thermohydrodynamic characteristics obtained by numerical results, appropriate experimental setup with accurate instrumentations was conducted. Based on presence and absence of porous media and solid rod inside of pipe, six conditions were compared for quantifying the heat transfer enhancement and effectiveness. Governing equations were discretized by finite volume method (FVM) and solved using the semi-implicit method for pressure linked equations (SIMPLE) algorithm and computational fluid dynamic (CFD) techniques. It was found that magnetic field, porous media, and solid rod increase heat transfer and pressure loss in the pipe such that solid rod has the best effect on heat transfer and worst effect on effectiveness.


Author(s):  
M. A. Abd Halim ◽  
N. A. R. Nik Mohd ◽  
M. N. Mohd Nasir ◽  
M. N. Dahalan

Induction system or also known as the breathing system is a sub-component of the internal combustion system that supplies clean air for the combustion process. A good design of the induction system would be able to supply the air with adequate pressure, temperature and density for the combustion process to optimizing the engine performance. The induction system has an internal flow problem with a geometry that has rapid expansion or diverging and converging sections that may lead to sudden acceleration and deceleration of flow, flow separation and cause excessive turbulent fluctuation in the system. The aerodynamic performance of these induction systems influences the pressure drop effect and thus the engine performance. Therefore, in this work, the aerodynamics of motorcycle induction systems is to be investigated for a range of Cubic Feet per Minute (CFM). A three-dimensional simulation of the flow inside a generic 4-stroke motorcycle airbox were done using Reynolds-Averaged Navier Stokes (RANS) Computational Fluid Dynamics (CFD) solver in ANSYS Fluent version 11. The simulation results are validated by an experimental study performed using a flow bench. The study shows that the difference of the validation is 1.54% in average at the total pressure outlet. A potential improvement to the system have been observed and can be done to suit motorsports applications.


Author(s):  
Eiman B Saheby ◽  
Xing Shen ◽  
Anthony P Hays ◽  
Zhang Jun

This study describes the aerodynamic efficiency of a forebody–inlet configuration and computational investigation of a drone system, capable of sustainable supersonic cruising at Mach 1.60. Because the whole drone configuration is formed around the induction system and the design is highly interrelated to the flow structure of forebody and inlet efficiency, analysis of this section and understanding its flow pattern is necessary before any progress in design phases. The compression surface is designed analytically using oblique shock patterns, which results in a low drag forebody. To study the concept, two inlet–forebody geometries are considered for Computational Fluid Dynamic simulation using ANSYS Fluent code. The supersonic and subsonic performance, effects of angle of attack, sideslip, and duct geometries on the propulsive efficiency of the concept are studied by solving the three-dimensional Navier–Stokes equations in structured cell domains. Comparing the results with the available data from other sources indicates that the aerodynamic efficiency of the concept is acceptable at supersonic and transonic regimes.


Author(s):  
Mohammad Mehdi Tavakol ◽  
Mohammad Eslami

Fluid flow around single or multiple bluff bodies mounted on a surface has great significance in science and engineering. Understanding the characteristics of different vortices formed around wall-mounted bodies is quite necessary for different applications. Although the case of a single surface mounted cube has been studied extensively, only little attention has been paid to the flow around two or more rectangular blocks in array. Therefore, a CFD code is developed to calculate three dimensional steady state laminar fluid flow around two cuboids of arbitrary size and configuration mounted on a surface in free stream conditions. The employed numerical scheme is finite volume and SIMPLE algorithm is used to treat pressure and velocity coupling. Results are presented for two rectangular blocks of the different size mounted on a surface in various inline arrangements. Streamlines are plotted for blocks of different size ratio. Velocity and pressure distributions are also plotted in the wake region behind the obstacles. It is shown that how the behavior of flow field and vortical structures depend on the respective size and location of the larger block in comparison with the case of two inline wall mounted cubes of the same size.


Geophysics ◽  
1989 ◽  
Vol 54 (3) ◽  
pp. 350-358 ◽  
Author(s):  
G. Nolet ◽  
R. Sleeman ◽  
V. Nijhof ◽  
B. L. N. Kennett

We present a simple algorithm for computing the acoustic response of a layered structure containing three‐dimensional (3-D) irregularities, using a locked‐mode approach and the Born approximation. The effects of anelasticity are incorporated by use of Rayleigh’s principle. The method is particularly attractive at somewhat larger offsets, but computations for near‐source offsets are stable as well, due to the introduction of anelastic damping. Calculations can be done on small minicomputers. The algorithm developed in this paper can be used to calculate the response of complicated models in three dimensions. It is more efficient than any other method whenever many sources are involved. The results are useful for modeling, as well as for generating test signals for data processing with realistic, model‐induced “noise.” Also, this approach provides an alternative to 2-D finite‐difference calculations that is efficient enough for application to large‐scale inverse problems. The method is illustrated by application to a simple 3-D structure in a layered medium.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ömer Akbal ◽  
Hakan F. Öztop ◽  
Nidal H. Abu-Hamdeh

Purpose The purpose of this paper is to make a three-dimensional computational analysis of melting in corrugated pipe inserted system filled with phase change material (PCM). The system was heated from the inner pipe, and temperature of the outer pipe was lower than that of inner pipe. Different geometrical ratio cases and two different temperature differences were tested for their effect on melting time. Design/methodology/approach A computational analysis through a pipe with corrugated pipe filled with PCM is analyzed. Finite volume method was applied with the SIMPLE algorithm method to solve the governing equations. Findings The results indicate that the geometrical parameters can be used to control the melting time inside the heat exchanger which, in turn, affect the energy efficiency. The fastest melting time is seen in Case 4 at the same temperature difference which is the major observation of the current work. Originality/value Originality of this work is to perform a three-dimensional analysis of melting of PCM in a corrugated pipe inserted pipe.


Water ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1698 ◽  
Author(s):  
Lin Li ◽  
David Zhu ◽  
Biao Huang

Rapid filling/emptying of pipes is commonly encountered in water supply and sewer systems, during which pressure transients may cause unexpected large pressure and/or geyser events. In the present study, a linearized analytical model is first developed to obtain the approximate solutions of the maximum pressure and the characteristics of pressure oscillations caused by the pressurization of trapped air in a horizontal pipe when there is no or insignificant air release. The pressure pattern is a typical periodic wave, analogous to sinusoidal motion. The oscillation period and the time when the pressure attains the peak value are significantly influenced by the driving pressure and the initial length of the entrapped air pocket. When there is air release through a venting orifice, analysis by a three-dimensional computational fluid dynamics model using ANSYS Fluent was also conducted to furnish insights and details of air–water interactions. Flow features associated with the pressurization and air release were examined, and an air–water interface deformation that one-dimensional models are incapable of predicating was presented. Modelling results indicate that the residual air in the system depends on the relative position of the venting orifice. There are mainly two types of pressure oscillation patterns: namely, long or short-period oscillations and waterhammer. The latter can be observed when the venting orifice is located near the end of the pipe where the air is trapped.


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