Comparison of 1-D vs 3-D Combustion Boundary Conditions for SI Engine Thermal Load Prediction

2013 ◽  
Author(s):  
O. Iqbal ◽  
S. Jonnalagedda ◽  
K. Arora ◽  
L. Zhong ◽  
S. Gaikwad
Keyword(s):  
Heat Transfer ◽  
Boundary Condition ◽  
Temperature Distribution ◽  
Boundary Conditions ◽  
Cylinder Head ◽  
Convective Boundary Condition ◽  
Combustion Model ◽  
Convective Boundary Conditions ◽  
Convective Boundary ◽  
Simulation Code

The thermal field generated in an engine block and cylinder head as a result of combustion loading is of paramount significance for structural durability. Computational fluid dynamics and heat transfer modeling provide strong tools; perhaps the best and most precise available for predicting thermal fields within cylinder head and engine block. However, an enduring challenge has been the temperature prediction on metal wall as a response to the time dependent fluctuations in the fluids. Fluid (coolant) flow in an engine is steady for a given engine speed and load, but combustion dynamics are inherently transient. In this study, an effective set of convective boundary condition data (as combustion load) is generated using two different approaches in a stand-alone simulation and mapped onto a decoupled Conjugate Heat Transfer (CHT) model to predict the temperature distribution in the engine. In the first approach, a predictive combustion model, tuned to dyno test data, is solved in a 1-D simulation code. This provides the cycle-averaged convective boundary condition that can be used for a CHT model as a uniform heat source. In the second, more detailed approach, in-cylinder combustion simulations involving transient piston and valve motion with flame propagation modeling are carried out using a 3-D simulation code. The 3-D methodology gives a detailed distribution of convective boundary conditions on the walls touching the combustion gases. In order to predict the gradients in heat transfer coefficient with high accuracy, the resulting temperature distribution from the CHT simulation is fed back into the combustion model to regenerate the set of convective boundary conditions. This process is repeated until a converged set of convective boundary conditions are obtained. In this paper engine temperature predictions obtained using combustion loads from both 1-D and 3-D approaches will be compared with the thermocouple data from engine dyno test.

Impact of surface temperature and convective boundary conditions on a Nanofluid flow over a radially stretched Riga plate

2021 ◽  
pp. 095440892110544
Author(s):  
K.V. Prasad ◽  
Hanumesh Vaidya ◽  
Fateh Mebarek-Oudina ◽  
Rajashekhar Choudhari ◽  
Kottakkaran Sooppy Nisar ◽  
...  
Keyword(s):  
Boundary Condition ◽  
Boundary Conditions ◽  
Surface Temperature ◽  
Surface Concentration ◽  
Mass Transfer Process ◽  
Convective Boundary Condition ◽  
Convective Boundary Conditions ◽  
Convective Boundary ◽  
Analytical Methodology ◽  
Riga Plate

The current work provides the optimal homotopic analytical methodology for the steady circulation over a non-isothermal radially stretched Riga plate/disc unit. The attributes of the heat, along with the mass transfer process, are assessed in the existence of variable transport and magnetic features. Radial stretched Riga disc is considered along with additional realistic boundary heating conditions, namely, prescribed surface temperature as well as prescribed surface concentration, convective boundary conditions and also zero mass flux concentration on the surface area of the Riga disc. The model tracks Brownian motion as well as the thermal diffusion of nanoparticles in fluid circulation all at once. Regulating equations, which are highly coupled, are changed right into non-dimensional equations using appropriate transformations of similarity. Through assembling series solutions, the resulting framework is planned and examined. Graphic summaries are offered for the rheological qualities of various parameters in size for velocity, temperature, as well as nanoparticles. The modified Hartman number improves the velocity distribution and reduces the temperature distribution in both prescribed surface temperature and convective boundary condition cases. The effect of the chemical reaction parameter shows the reduced concentration distribution for the prescribed surface temperature case. In contrast, it is precisely the opposite in the convective boundary condition case.

Unsteady and porous media flow of reactive non-Newtonian fluids subjected to buoyancy and suction/injection

2015 ◽  
Vol 25 (7) ◽  
pp. 1682-1704 ◽  
Author(s):  
Tirivanhu Chinyoka ◽  
Daniel Oluwole Makinde
Keyword(s):  
Heat Transfer ◽  
Porous Media ◽  
Boundary Conditions ◽  
Flow Velocity ◽  
Flow System ◽  
Finite Difference Methods ◽  
Porous Media Flow ◽  
Convective Boundary Conditions ◽  
Convective Boundary ◽  
Content Type

Purpose – The purpose of this paper is to examine the unsteady pressure-driven flow of a reactive third-grade non-Newtonian fluid in a channel filled with a porous medium. The flow is subjected to buoyancy, suction/injection asymmetrical and convective boundary conditions. Design/methodology/approach – The authors assume that exothermic chemical reactions take place within the flow system and that the asymmetric convective heat exchange with the ambient at the surfaces follow Newton’s law of cooling. The authors also assume unidirectional suction injection flow of uniform strength across the channel. The flow system is modeled via coupled non-linear partial differential equations derived from conservation laws of physics. The flow velocity and temperature are obtained by solving the governing equations numerically using semi-implicit finite difference methods. Findings – The authors present the results graphically and draw qualitative and quantitative observations and conclusions with respect to various parameters embedded in the problem. In particular the authors make observations regarding the effects of bouyancy, convective boundary conditions, suction/injection, non-Newtonian character and reaction strength on the flow velocity, temperature, wall shear stress and wall heat transfer. Originality/value – The combined fluid dynamical, porous media and heat transfer effects investigated in this paper have to the authors’ knowledge not been studied. Such fluid dynamical problems find important application in petroleum recovery.

Numerical investigation of laminar forced convection for a non-Newtonian nanofluids flowing inside an elliptical duct under convective boundary condition

2019 ◽  
Vol 29 (1) ◽  
pp. 334-364 ◽  
Author(s):  
Haroun Ragueb ◽  
Kacem Mansouri
Keyword(s):  
Heat Transfer ◽  
Boundary Condition ◽  
Heat Transfer Coefficient ◽  
Fluid Flow ◽  
Transfer Coefficient ◽  
Convective Boundary Condition ◽  
Bulk Temperature ◽  
Convective Boundary ◽  
Content Type ◽  
The Heat Transfer Coefficient

PurposeThe purpose of this study is to investigate the thermal response of the laminar non-Newtonian fluid flow in elliptical duct subjected to a third-kind boundary condition with a particular interest to a non-Newtonian nanofluid case. The effects of Biot number, aspect ratio and fluid flow behavior index on the heat transfer have been examined carefully.Design/methodology/approachFirst, the mathematical problem has been formulated in dimensionless form, and then the curvilinear elliptical coordinates transform is applied to transform the original elliptical shape of the duct to an equivalent rectangular numerical domain. This transformation has been adopted to overcome the inherent mathematical deficiency due to the dependence of the ellipsis contour on the variables x and y. The yielded problem has been successfully solved using the dynamic alternating direction implicit method. With the available temperature field, several parameters have been computed for the analysis purpose such as bulk temperature, Nusselt number and heat transfer coefficient.FindingsThe results showed that the use of elliptical duct enhances significantly the heat transfer coefficient and reduces the duct’s length needed to achieve the thermal equilibrium. For some cases, the reduction in the duct’s length can reach almost 50 per cent compared to the circular pipe. In addition, the analysis of the non-Newtonian nanofluid case showed that the addition of nanoparticles to the base fluid improves the heat transfer coefficient up to 25 per cent. The combination of using an elliptical duct and the addition of nanoparticles has a spectacular effect on the overall heat transfer coefficient with an enhancement of 50-70 per cent. From the engineering applications view, the results demonstrate the potential of elliptical duct in building light-weighted compact shell-and-tube heat exchangers.Originality/valueA complete investigation of the heat transfer of a fully developed laminar flow of power law fluids in elliptical ducts subject to the convective boundary condition with application to non-Newtonian nanofluids is addressed.

Analytical Solution for Solid Cylindrical Heat Source Model With Convective Boundary Condition

2019 ◽  
Vol 141 (12) ◽  
Author(s):  
Yang Zhou ◽  
Cheng Xu ◽  
David Sego ◽  
Dong-hai Zhang
Keyword(s):  
Heat Transfer ◽  
Boundary Condition ◽  
Analytical Solution ◽  
Heat Source ◽  
Groundwater Flow ◽  
Convective Boundary Condition ◽  
Convective Boundary ◽  
Energy Pile ◽  
Special Cases ◽  
Scs Model

Abstract The energy pile technology has been widely used, and the solid cylindrical heat source (SCS) model is usually adopted to describe the heat transfer process between the energy pile and the surrounding soil. This paper investigates the SCS model with a convective boundary condition (SCS-3 model), and realistic conditions such as transversely isotropic ground and groundwater flow are all included in the model. An analytical solution for the problem is established using Green's function method and the theory of moving heat sources. Solutions for the SCS model with a boundary condition of the first kind (SCS-1 model) and for the line source (LS) model with a convective boundary condition (LS-3 model) are recovered as special cases of the solution in this paper. Computational examples are presented, and comparisons between different models are made. First, the SCS-1 model is compared with the SCS-3 model, showing the error caused by neglecting the surface convective effect. Second, the LS-3 model is compared with the SCS-3 model, showing the error associated with neglecting the size of heat source. The effects of groundwater flow velocity and convective heat transfer coefficient on the temporal and spatial variations of these errors are also investigated.

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