Transient Heat Flux Measurements in a Divided-Chamber Diesel Engine

1985 ◽  
Vol 107 (2) ◽  
pp. 439-444 ◽  
Author(s):  
A. C. Alkidas ◽  
R. M. Cole

Transient surface heat flux measurements were performed at several locations on the cylinder head of a divided-chamber diesel engine. The local heat flux histories were found to be significantly different. These differences are attributed to the spatial nonuniformity of the fluid motion and combustion. Both local time-averaged and local peak heat fluxes decreased with decreasing speed and load. Retarding the combustion timing beyond TDC decreased the peak heat flux in the antechamber but increased the peak heat flux in the main chamber. This is attributed to the relative increase in the portion of fuel that burns in the main chamber with retarded combustion timing.

2014 ◽  
Vol 271 ◽  
pp. 48-54 ◽  
Author(s):  
K.A. Murashko ◽  
A.V. Mityakov ◽  
J. Pyrhönen ◽  
V.Y. Mityakov ◽  
S.S. Sapozhnikov

Author(s):  
Sergey Z. Sapozhnikov ◽  
Vladimir Yu. Mityakov ◽  
Andrey V. Mityakov ◽  
Andrey A. Snarskii ◽  
Maxim I. Zhenirovskyy

The local heat flux measurements are limited by low working temperature of the gradient heat flux sensors (GHFS) [1–3]. The novel heterogeneous sensors (HGHFS) made from metal-metal or metal-semiconductor layered composites (so-called anisotropic thermoelements) have high temperature level of 1300 K and more. Theory of the HGHFS allows to choose thickness and angle of inclination for the layers of composite, and to forecast volt-watt sensitivity. The sensitivity of metal-metal sensors is typically on the order of 0.02 to 0.5 mV/W, and it is much beyond when semiconductors are used. HGHFS are used for a first time for heat flux measurements in the furnace of the industrial boiler which is in operating of the Thermal Power Plant (fossil fuel power plant) in the city of Kirov (Russia). The local heat flux at the surface of refractory-faced water wall is measured in different regimes of operating. It is also shown that HGHFS may be used as indicator of furnace slugging. Small sizes (minimally 2×2×0.1 mm) and high working temperature of the HGHFS are useful for heat transfer investigations.


2009 ◽  
Vol 34 (24) ◽  
pp. 9857-9868 ◽  
Author(s):  
J. Demuynck ◽  
N. Raes ◽  
M. Zuliani ◽  
M. De Paepe ◽  
R. Sierens ◽  
...  

1973 ◽  
Vol 95 (4) ◽  
pp. 477-482 ◽  
Author(s):  
J. H. Lienhard ◽  
V. K. Dhir ◽  
D. M. Riherd

Experimental data obtained at both earth-normal and elevated gravity, in a variety of organic liquids and water, are used to verify the hydrodynamic theory for the peak pool boiling heat flux on flat plates. A modification of Zuber’s formula, which gives a 14 percent higher peak heat flux, is verified as long as the flat plate is more than three Taylor wavelengths across. For smaller heaters, the hydrodynamic theory requires a wide variation in heat flux owing to discontinuities in the number of escaping jets. Data for smaller plates bear out this predicted variation with heat fluxes that range between 40 percent and 235 percent of Zuber’s predicted value. Finally, a method is suggested for augmenting the peak heat flux on large heaters, and shown experimentally to be viable.


1987 ◽  
Vol 109 (2) ◽  
pp. 193-199 ◽  
Author(s):  
A. C. Alkidas

The influences of operational parameters on the heat release and heat transfer characteristics of a divided-chamber diesel engine were examined. Increasing the fuel-air ratio increased the heat release rate, as expected, and increased the duration of combustion. Near the beginning and end of combustion the mass-burned rate was found to increase in direct proportion to an increase of engine speed. In contrast, in the central part of the combustion duration, the mass-burned rate was found to increase at a higher rate than engine speed. For motored conditions, the computed area-averaged heat-flux histories were found to be in reasonable agreement with the corresponding measured local heat-flux histories.


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