A Numerical Study on Predicting Combustion Chamber Wall Surface Temperature Distributions in a Diesel Engine and their Effects on Combustion, Emission and Heat Loss Characteristics by Using a 3D-CFD Code Combined with a Detailed Heat Transfer Model

2015 ◽  
Author(s):  
Akira Kikusato ◽  
Jin Kusaka ◽  
Yasuhiro Daisho
Keyword(s):  
Heat Transfer ◽  
Diesel Engine ◽  
Surface Temperature ◽  
Combustion Chamber ◽  
Numerical Study ◽  
Transfer Model ◽  
Wall Surface ◽  
Temperature Distributions ◽  
Combustion Emission ◽  
Wall Surface Temperature

scholarly journals Study on Flow and Heat Transfer Characteristics of Supercritical Kerosene in a Round Tube

2020 ◽  
Vol 316 ◽  
pp. 03003
Author(s):  
Feng Gao ◽  
Qian Zhang ◽  
Hongyu Xiao ◽  
Fengli Chen ◽  
Xuefeng Xia
Keyword(s):  
Heat Transfer ◽  
Surface Temperature ◽  
Inlet Temperature ◽  
Wall Surface ◽  
Heat Transfer Characteristics ◽  
Navier Stokes Equation ◽  
Transfer Characteristics ◽  
Flow And Heat Transfer ◽  
Wall Surface Temperature ◽  
Central Flow

The finite volume discrete solution of the Navier-Stokes equation and the RNG model of the turbulence model are used to numerically simulate the flow and heat transfer characteristics of supercritical kerosene in a circular tube. The results show that as the inlet mass flow increases, the wall surface temperature and the central flow oil temperature gradually decrease, and the pressure loss becomes larger. As the inlet temperature increases, the wall surface temperature and the central flow oil temperature both increase. When the heat flux density is constant, as the pressure increases, the deterioration of heat transfer will be weakened, and increasing the pressure can improve the effect of convection heat transfer.

scholarly journals Numerical Study of the Thermal Model on High Uniformity Temperature Test Platform

2019 ◽  
Vol 256 ◽  
pp. 03003
Author(s):  
Zijuan Wang ◽  
Ying Zhou ◽  
Han Xiao ◽  
Shao Jingyi
Keyword(s):  
Heat Transfer ◽  
Surface Temperature ◽  
Numerical Study ◽  
Radiation Heat Transfer ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Conductive Heat ◽  
Temperature Uniformity ◽  
Test Platform ◽  
Background Temperature

The surface temperature uniformity of a test platform with an effective test area of 600 mm × 600 mm was numerically studied. The conductive heat transfer model for the test platform and the device under test (DUT) installed on the surface was established in the present work, as well as the radiation heat transfer model from the platform surface to the background temperature. The platform surface was divided into 5 or 9 regions where heated independently to make the surface temperature consistent. The temperature uniformity of these two partition designs was compared. The result shows that the 9 regions design has higher temperature uniformity at both target temperatures of -10°C and +45°C.

High-output diesel engine heat transfer: Part 1 - comparison between piston heat flux and global energy balance

2021 ◽  
pp. 146808742110170
Author(s):  
Eric Gingrich ◽  
Michael Tess ◽  
Vamshi Korivi ◽  
Jaal Ghandhi
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Diesel Engine ◽  
Surface Temperature ◽  
Fast Response ◽  
Temperature Data ◽  
Start Of Injection ◽  
Local Measurements ◽  
Surface Temperature Data ◽  
High Output

High-output diesel engine heat transfer measurements are presented in this paper, which is the first of a two-part series of papers. Local piston heat transfer, based on fast-response piston surface temperature data, is compared to global engine heat transfer based on thermodynamic data. A single-cylinder research engine was operated at multiple conditions, including very high-output cases – 30 bar IMEPg and 250 bar in-cylinder pressure. A wireless telemetry system was used to acquire fast-response piston surface temperature data, from which heat flux was calculated. An interpolation and averaging procedure was developed and a method to recover the steady-state portion of the heat flux based on the in-cylinder thermodynamic state was applied. The local measurements were spatially integrated to find total heat transfer, which was found to agree well with the global thermodynamic measurements. A delayed onset of the rise of spatially averaged heat flux was observed for later start of injection timings. The dataset is internally consistent, for example, the local measurements match the global values, which makes it well suited for heat transfer correlation development; this development is pursued in the second part of this paper.

Analysis and Modelling of Temperature at Lake’s Water – Atmosphere Interface

2021 ◽  
Author(s):  
Vassilis Z. Antonopoulos ◽  
Soultana K. Gianniou
Keyword(s):  
Heat Transfer ◽  
Energy Balance ◽  
Surface Temperature ◽  
Water Surface ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Net Radiation ◽  
Water Surface Temperature ◽  
Simulation Results ◽  
Input Variables

Abstract The knowledge of micrometeorological conditions on water surface of impoundments is crucial for the better modeling of the temperature and water quality parameters distribution in the water body and against the climatic changes. Water temperature distribution is an important factor that affects most physical, chemical and biological processes and reactions occurring in lakes. In this work, different processes of water surface temperature of lake’s estimation based on the energy balance method are considered. The daily meteorological data and the simulation results of energy balance components from an integrated heat transfer model for two complete years as well as the lake’s characteristics for Vegoritis lake in northern Greece were used is this analysis.The simulation results of energy balance components from a heat transfer model are considered as the reference and more accurate procedure to estimate water surface temperature. These results are used to compare the other processes. The examined processes include a) models of heat storage changes in relationship to net radiation (Qt(Rn) values, b) net radiation estimation with different approaches, as the process of Slob’s equation with adjusted coefficients to lake data, and c) ANNs models with different architecture and input variables. The results show that the model of heat balance describes the water surface temperature with high accuracy (r2=0.916, RMSE=2.422oC). The ANN(5,6,1) model in which Tsw(i-1) is incorporated in the input variables was considered the better of all other ANN structures (r2=0.995, RMSE=0.490oC). The use of different approaches for simulating net radiation (Rn) and Qt(Rn) in the equation of water surface temperature gives results with lower accuracy.

Numerical Simulation of Heat Transfer in Laminar Natural Convection of Mixed Newtonian-Non-Newtonian and Pure Non-Newtonian Nanofluids in a Square Enclosure

2021 ◽  
pp. 1-44
Author(s):  
Ajay Vallabh ◽  
P.S. Ghoshdastidar
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Base Fluid ◽  
Volume Fraction ◽  
Numerical Study ◽  
Transfer Model ◽  
Nanoparticle Concentration ◽  
Left Wall ◽  
Square Enclosure ◽  
First Case

Abstract This paper presents a steady-state heat transfer model for the natural convection of mixed Newtonian-Non-Newtonian (Alumina-Water) and pure Non-Newtonian (Alumina-0.5 wt% Carboxymethyl Cellulose (CMC)/Water) nanofluids in a square enclosure with adiabatic horizontal walls and isothermal vertical walls, the left wall being hot and the right wall cold. In the first case the nanofluid changes its Newtonian character to Non-Newtonian past 2.78% volume fraction of the nanoparticles. In the second case the base fluid itself is Non-Newtonian and the nanofluid behaves as a pure Non-Newtonian fluid. The power-law viscosity model has been adopted for the non-Newtonian nanofluids. A finite-difference based numerical study with the Stream function-Vorticity-Temperature formulation has been carried out. The homogeneous flow model has been used for modelling the nanofluids. The present results have been extensively validated with earlier works. In Case I the results indicate that Alumina-Water nanofluid shows 4% enhancement in heat transfer at 2.78% nanoparticle concentration. Following that there is a sharp decline in heat transfer with respect to that in base fluid for nanoparticle volume fractions equal to and greater than 3%. In Case II Alumina-CMC/Water nanofluid shows 17% deterioration in heat transfer with respect to that in base fluid at 1.5% nanoparticle concentration. An enhancement in heat transfer is observed for increase in hot wall temperature at a fixed volume fraction of nanoparticles, for both types of nanofluid.

Numerical Study on 3D Coupled Heat Transfer of Thrust Chamber with Regenerative Cooling

2011 ◽  
Vol 52-54 ◽  
pp. 1057-1061
Author(s):  
Tao Nie ◽  
Wei Qiang Liu
Keyword(s):  
Heat Transfer ◽  
Optimization Design ◽  
Numerical Study ◽  
Computing Time ◽  
Three Dimensional ◽  
Geometrical Model ◽  
Performance Estimation ◽  
Transfer Model ◽  
Empirical Formulas ◽  
Coupled Heat Transfer

To obtain temperature distribution in regenerative-cooled liquid propellant rocket nozzle quickly and accurately, three-dimensional numerical simulation employed using empirical formulas. A reduced one-dimensional model is employed for the coolant flow and heat transfer, while three dimensional heat transfer model is used to calculate the coupling heat transfer through the wall. The geometrical model is subscale hot-firing chamber. The numerical results agree well with experimental data, while temperature field in nozzle obtained. In terms of computing time and accuracy of results, this method can provide a reference for optimization design and performance estimation.

A Numerical Study on the Slab Heating Characteristics in a Reheating Furnace With the Formation and Growth of Scale on the Slab Surface

2009 ◽  
Author(s):  
Dong Eun Lee ◽  
Jung Hyun Jang ◽  
Man Young Kim
Keyword(s):  
Heat Transfer ◽  
Present Model ◽  
Numerical Study ◽  
Convection Heat Transfer ◽  
Radiant Heat ◽  
Transfer Model ◽  
Radiant Heat Transfer ◽  
Reheating Furnace ◽  
Combustion Gases ◽  
Scale Layer

In this work, the development of a mathematical heat transfer model for a walking-beam type reheating furnace is described and preliminary model predictions are presented. The model can predict the heat flux distribution within the furnace and the temperature distribution in the slab throughout the reheating furnace process by considering the heat exchange between the slab and its surroundings, including the radiant heat transfer among the slabs, the skids, the hot combustion gases and the furnace wall as well as the gas convection heat transfer in the furnace. In addition, present model is designed to be able to predict the formation and growth of the scale layer on the slab in order to investigate its effect on the slab heating. A comparison is made between the predictions of the present model and the data from an in situ measurement in the furnace, and a reasonable agreement is found. The results of the present simulation show that the effect of the scale layer on the slab heating is considerable.

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