Empirical Formula for Instantaneous Heat Transfer Coefficient in Spark Ignition Engine

1997 ◽  
Author(s):  
Sung Bin Han ◽  
Yon Jong Chung ◽  
Young Jik Kwon ◽  
Songyol Lee
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Empirical Formula ◽  
Spark Ignition ◽  
Spark Ignition Engine

CFD Study of Heat Transfer in a Spark-Ignition Engine Combustion Chamber

2006 ◽  
Vol 129 (5) ◽  
pp. 609-616 ◽  
Author(s):  
A. R. Noori ◽  
M. Rashidi
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Temporal Variation ◽  
Combustion Chamber ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Si Engine ◽  
Engine Combustion

The objective of this study is the thermal investigation of a typical spark-ignition (SI) engine combustion chamber with particular focus in determination of the locations where the heat flux and heat transfer coefficient are highest. This subject is an important key for some design purposes especially thermal loading of the piston and cylinder head. To this end, CFD simulation using the KIVA-3V CFD code on a PC platform for flow, combustion, and heat transfer in a typical SI engine has been performed. Some results including the temporal variation of the area-averaged heat flux and heat transfer coefficient on the piston, combustion chamber, and cylinder wall are presented. Moreover, the temporal variation of the local heat transfer coefficient and heat flux along a centerline on the piston as well as a few locations on the combustion chamber wall are shown. The investigation reveals that during the combustion period, the heat flux and heat transfer coefficient vary substantially in space and time due to the transient nature of the flame propagation. For example, during the early stages of the flame impingement on the wall, the heat flux undergoes a rapid increase by as much as around 10 times the preimpingement level. In other words, the initial rise of the heat flux at any location is related to the time of the flame arrival at that location.

Numerical Simulation of Convective Heat Transfer in a Spark Ignition Engine

2008 ◽  
Author(s):  
Arash Mohammadi ◽  
Seyed Ali Jazayeri ◽  
Masoud Ziabasharhagh
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Combustion Chamber ◽  
Spark Ignition Engine ◽  
Cylinder Wall ◽  
Single Cylinder Engine ◽  
Crank Angle ◽  
Exhaust Valves

A computational fluid dynamics code is applied to simulate fluid flow and combustion in a four-stroke single cylinder engine with flat combustion chamber geometry. Heat flux and heat transfer coefficient on the cylinder head, cylinder wall, piston, intake and exhaust valves are determined. Result for a certain condition is compared for total heat transfer coefficient of the cylinder engine with available correlation proposed by experimental measurement in the literature and close agreement is observed. It is observed that the value of heat flux and heat transfer coefficient varies considerably in different positions of the combustion chamber, but the trend with crank angle is almost the same.

The Analysis of Square Enclosure Air Layer's Heat Transfer in Building Materials

2013 ◽  
Vol 291-294 ◽  
pp. 971-975
Author(s):  
Gang Chen ◽  
Ding Sun ◽  
Xin Cheng
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Empirical Formula ◽  
Building Materials ◽  
Square Enclosure ◽  
Fluent Software ◽  
Simulation Results ◽  
The Heat Transfer Coefficient ◽  
Different Thickness

This paper using Fluent Software to numerical simulate the heat transfer in square enclosure cavity air layer in different thickness and heights.By analysed the simulation results, we found that the best thickness in it is 20mm .Then we respectively used empirical formula as well as simulation results to calculated the heat transfer coefficient in air layer. The results showed that both numerical were very close, the calculation of heat transfer coefficient was consistent with the simulation results obtained by the rules.

Evaporation of lignin-lean black liquor

TAPPI Journal ◽  
2015 ◽  
Vol 14 (7) ◽  
pp. 441-450
Author(s):  
HENRIK WALLMO, ◽  
ULF ANDERSSON ◽  
MATHIAS GOURDON ◽  
MARTIN WIMBY
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Black Liquor ◽  
Salt Content ◽  
Solubility Limit ◽  
Lignin Removal ◽  
Kraft Black Liquor ◽  
Black Liquors ◽  
The Heat Transfer Coefficient

Many of the pulp mill biorefinery concepts recently presented include removal of lignin from black liquor. In this work, the aim was to study how the change in liquor chemistry affected the evaporation of kraft black liquor when lignin was removed using the LignoBoost process. Lignin was removed from a softwood kraft black liquor and four different black liquors were studied: one reference black liquor (with no lignin extracted); two ligninlean black liquors with a lignin removal rate of 5.5% and 21%, respectively; and one liquor with maximum lignin removal of 60%. Evaporation tests were carried out at the research evaporator in Chalmers University of Technology. Studied parameters were liquor viscosity, boiling point rise, heat transfer coefficient, scaling propensity, changes in liquor chemical composition, and tube incrustation. It was found that the solubility limit for incrustation changed towards lower dry solids for the lignin-lean black liquors due to an increased salt content. The scaling obtained on the tubes was easily cleaned with thin liquor at 105°C. It was also shown that the liquor viscosity decreased exponentially with increased lignin outtake and hence, the heat transfer coefficient increased with increased lignin outtake. Long term tests, operated about 6 percentage dry solids units above the solubility limit for incrustation for all liquors, showed that the heat transfer coefficient increased from 650 W/m2K for the reference liquor to 1500 W/m2K for the liquor with highest lignin separation degree, 60%.

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