CRFD-Simulation of Large-Bore Diesel Engines

(This project is conducted in collaboration with the Engine Research Center of the University of Wisconsin-Madison.)

 

 

Environmental concerns and the associated demand for pollution control have become an important issue in the design process of combustion engines. Recently developed methods in computational reactive fluid dynamics (CRFD) have become a powerful tool in the investigation of the fundamental mechanisms which  govern the in-cylinder processes in a reciprocating engine. In contrast to the traditional techniques which have mainly been restricted to thermodynamic considerations, CRFD methods resolve the three dimensional flow, spray and combustion processes and thus provide a  means for the prediction of pollutants such as soot, nitric oxides and unburned hydrocarbons, as well as the further optimization of the combustion process.

The objective of this project is the closer coordination of the research efforts between universities and industries through complementary developments, exchange of know-how and the transfer of technologies. In particular, the integration of CRFD codes in the design process of engines plays an important part in this common effort; the improvement of existing models and the development of new computational methods and techniques are the key for a success of this project.
 

 CRFD-Methods Applied in the Simulation of the Sulzer RTA58T Diesel Engine

engine type two-stroke, uniflow-scavenged, one exhaust valve
bore [mm] x stroke [mm] 580 x 2416
engine speed [rpm] 103
injectors three peripheral, prototype nozzles with five orifices
power output [kW/cyl] 2000
 Table 1: Specifications of the Sulzer RTA58T DI diesel engine.
 
Figure 1: Cylinder pressures (left) and rate of heat release [ROHR] as a function of crank angles after start of injection [deg ASI] for the Sulzer RTA58T. The dent in the heat release curve is the result of spray interactions.
 
 Figure 2: Reaction rates in a horizontal plane through the injectors of the Sulzer RTA58T at 9 deg ASI (left) and at 13 deg ASI (right). The decrease in the reaction rate is due to spray interactions and explains the dent in the heat release curve in figure 1.
 
Figure3: Oxygen mass fractions in a horizontal plane through the injectors of the Sulzer RTA58T at 9 deg ASI (left) and at 13 deg ASI (right). Regions of low oxygen concentration due to combustion (blue-green coloring) interact with the main reaction region near the nozzle exit of the neighbouring spray. This explains the reduction in the reaction rate illustrated in figure 2.
 

For further information please contact:
Franz.X. Tanner
Dept. of Mathematical Sciences
Michigan Technological University
1400 Townsend Drive, 223C Fisher Hall
Houghton, MI 49931-1295, U.S.A.
e-mail:     tanner@mtu.edu

 
German. Weisser
Research & Development
Waertsilae NSD Switzerland Ltd.
PO Box 414
CH-8401 Winterthur, Switzerland
e-mail:   german.weisser@wartsila-nsd.com
Rolf D. Reitz
Engine Research Center
University of Wisconsin
Madison, WI 53706-1572, U.S.A.
phone: +01 608 262 0145
fax: +01 608 262 6707
           e-mail: reitz@me.engr.wisc.edu
 

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