Piston-Liner Thermal Resistance Model for Diesel Engine Simulation: Part 1: Formulation and Tuning

A simple, effective and computationally economical piston-liner thermal resistance model for diesel engine simulation is described. In the model, the detailed shape of the piston and its axial movement and interaction with liner nodes are all taken into account. An imaginary node within the piston provides the necessary temperature difference between the piston and the liner nodes for conductive heat transfer, which is expected to reverse its direction with liner insulation. In the liner, an axially symmetric two-dimensional heat-transfer model is used. Later the piston-liner model is tuned for the experimental single cylinder, direct injection, Petter PH 1W engine used at Bath University, against the experimental piston temperature and liner temperature distribution.

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Piston-Liner Thermal Resistance Model for Diesel Engine Simulation: Part 2: Application to various Insulation Schemes

Proceedings of the Institution of Mechanical Engineers Part C Mechanical Engineering Science ◽

10.1243/pime_proc_1991_205_130_02 ◽

1991 ◽

Vol 205 (5) ◽

pp. 353-361 ◽

Cited By ~ 1

Author(s):

Y Rasihhan ◽

F J Wallace

Keyword(s):

Diesel Engine ◽

Temperature Distribution ◽

Thermal Resistance ◽

Heat Fluxes ◽

Engine Simulation ◽

Resistance Model

The piston-liner thermal resistance model, developed in Part 1, is applied to various piston and/or liner insulation schemes. The effects of insulation on piston-liner conduction and gas to wall heat fluxes and liner temperature distribution are examined. The small effect of insulation of the middle and lower parts of the liner is clearly shown.

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The Interface Thermal Resistance Evolution between Carbide-Bonded Graphene Coating and Polymer in Rapid Molding for Microlens Array

Polymers ◽

10.3390/polym13142334 ◽

2021 ◽

Vol 13 (14) ◽

pp. 2334

Author(s):

Xiaohua Liu ◽

Cheng Guo ◽

Yandong Liu ◽

Feng Wang ◽

Yanfeng Feng

Keyword(s):

Heat Transfer ◽

Thermal Resistance ◽

Rapid Heating ◽

Microlens Array ◽

Heating Process ◽

Transfer Model ◽

3D Graphene ◽

Resistance Evolution ◽

Interface Thermal Resistance ◽

Resistance Model

Surface rapid heating process is an efficient and green method for large-volume production of polymer optics by adopting 3D graphene network coated silicon molds with high thermal conductivity. Nevertheless, the heat transfer mechanism including the interface thermal resistance evolution between 3D graphene network coating and polymer has not been thoroughly revealed. In this study, the interface thermal resistance model was established by simplifying the contact situation between the coating and polymethylmethacrylate (PMMA), and then embedding into the finite element method (FEM) model to study the temperature variations of PMMA in surface rapid heating process. Heating experiments for graphene network were then carried out under different currents to provide the initial heat for heat transfer model. In addition, residual stress of the PMMA lens undergoing the non-uniform thermal history during molding was presented by the simulation model together. Finally, the optimal molding parameters including heating time and pressure will be determined according to calculation results of the interface thermal resistance model and microlens array molding experiment was conducted to illustrate that the interface thermal resistance model can predict the temperature of the polymer to achieve a better filling of microlens array with smooth surface and satisfactory optical performance.

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Nondegeneracy of optimality conditions in control problems for a radiative–conductive heat transfer model

Applied Mathematics and Computation ◽

10.1016/j.amc.2016.05.036 ◽

2016 ◽

Vol 289 ◽

pp. 371-380 ◽

Cited By ~ 3

Author(s):

Alexander Yu. Chebotarev ◽

Andrey E. Kovtanyuk ◽

Gleb V. Grenkin ◽

Nikolai D. Botkin ◽

Karl-Heinz Hoffmann

Keyword(s):

Heat Transfer ◽

Optimality Conditions ◽

Heat Transfer Model ◽

Conductive Heat Transfer ◽

Control Problems ◽

Transfer Model ◽

Conductive Heat

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Transient Behavior of Glow Plugs in Direct-Injection Natural Gas Engines

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4006692 ◽

2012 ◽

Vol 134 (9) ◽

Cited By ~ 12

Author(s):

Stewart Xu Cheng ◽

James S. Wallace

Keyword(s):

Heat Transfer ◽

Natural Gas ◽

Direct Injection ◽

High Surface ◽

Cold Start ◽

Transfer Model ◽

Ignition Process ◽

Computational Domain ◽

Glow Plug ◽

Natural Gas Engines

Glow plugs are a possible ignition source for direct injected natural gas engines. This ignition assistance application is much different than the cold start assist function for which most glow plugs have been designed. In the cold start application, the glow plug is simply heating the air in the cylinder. In the cycle-by-cycle ignition assist application, the glow plug needs to achieve high surface temperatures at specific times in the engine cycle to provide a localized source of ignition. Whereas a simple lumped heat capacitance model is a satisfactory representation of the glow plug for the air heating situation, a much more complex situation exists for hot surface ignition. Simple measurements and theoretical analysis show that the thickness of the heat penetration layer is small within the time scale of the ignition preparation period (1–2 ms). The experiments and analysis were used to develop a discretized representation of the glow plug domain. A simplified heat transfer model, incorporating both convection and radiation losses, was developed for the discretized representation to compute heat transfer to and from the surrounding gas. A scheme for coupling the glow plug model to the surrounding gas computational domain in the KIVA-3V engine simulation code was also developed. The glow plug model successfully simulates the natural gas ignition process for a direct-injection natural gas engine. As well, it can provide detailed information on the local glow plug surface temperature distribution, which can aid in the design of more reliable glow plugs.

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Experimental Investigation of Heat Transfer in Impingement Air Cooled Plate Fin Heat Sinks

Journal of Electronic Packaging ◽

10.1115/1.2351906 ◽

2005 ◽

Vol 128 (4) ◽

pp. 412-418 ◽

Cited By ~ 21

Author(s):

Zhipeng Duan ◽

Y. S. Muzychka

Keyword(s):

Heat Transfer ◽

Experimental Data ◽

Thermal Resistance ◽

Thermal Performance ◽

Heat Transfer Model ◽

Heat Sinks ◽

Transfer Model ◽

Transfer Coefficients ◽

Developing Flow ◽

Rectangular Channels

Impingement cooling of plate fin heat sinks is examined. Experimental measurements of thermal performance were performed with four heat sinks of various impingement inlet widths, fin spacings, fin heights, and airflow velocities. The percent uncertainty in the measured thermal resistance was a maximum of 2.6% in the validation tests. Using a simple thermal resistance model based on developing laminar flow in rectangular channels, the actual mean heat transfer coefficients are obtained in order to develop a simple heat transfer model for the impingement plate fin heat sink system. The experimental results are combined into a dimensionless correlation for channel average Nusselt number Nu∼f(L*,Pr). We use a dimensionless thermal developing flow length, L*=(L∕2)∕(DhRePr), as the independent parameter. Results show that Nu∼1∕L*, similar to developing flow in parallel channels. The heat transfer model covers the practical operating range of most heat sinks, 0.01<L*<0.18. The accuracy of the heat transfer model was found to be within 11% of the experimental data taken on four heat sinks and other experimental data from the published literature at channel Reynolds numbers less than 1200. The proposed heat transfer model may be used to predict the thermal performance of impingement air cooled plate fin heat sinks for design purposes.

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Effective Thermal Conductivity of Submicron Powders: A Numerical Study

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.846.500 ◽

2016 ◽

Vol 846 ◽

pp. 500-505

Author(s):

Wei Jing Dai ◽

Yi Xiang Gan ◽

Dorian Hanaor

Keyword(s):

Heat Transfer ◽

Thermal Conductivity ◽

Thermal Resistance ◽

Effective Thermal Conductivity ◽

Granular Materials ◽

Gas Phase ◽

Numerical Study ◽

Transfer Model ◽

Size Of Particles ◽

Contact Unit

Effective thermal conductivity is an important property of granular materials in engineering applications and industrial processes, including the blending and mixing of powders, sintering of ceramics and refractory metals, and electrochemical interactions in fuel cells and Li-ion batteries. The thermo-mechanical properties of granular materials with macroscopic particle sizes (above 1 mm) have been investigated experimentally and theoretically, but knowledge remains limited for materials consisting of micro/nanosized grains. In this work we study the effective thermal conductivity of micro/nanopowders under varying conditions of mechanical stress and gas pressure via the discrete thermal resistance method. In this proposed method, a unit cell of contact structure is regarded as one thermal resistor. Thermal transport between two contacting particles and through the gas phase (including conduction in the gas phase and heat transfer of solid-gas interfaces) are the main mechanisms. Due to the small size of particles, the gas phase is limited to a small volume and a simplified gas heat transfer model is applied considering the Knudsen number. During loading, changes in the gas volume and the contact area between particles are simulated by the finite element method. The thermal resistance of one contact unit is calculated through the combination of the heat transfer mechanisms. A simplified relationship between effective thermal conductivity and loading pressure can be obtained by integrating the contact units of the compacted powders.

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