2,089,394 research outputs found
Star Trek : Arbeitsbibliographie
No full textEine erste Fassung der folgenden Bibliographie haben wir in: Faszinierend! STAR TREK und die Wissenschaften. 2. (hrsg. v. Nina Rogotzki [...]. Kiel: Ludwig 2003, S. 222-240) vorgestellt
STAR General Assembly February 2019
No full textReport of the STAR research unit General Assembly during the Second STAR Workshop
Sierra Club Lone Star Chapter Newsletter
No full textSierra Club, Lone Star Chapter newsletter regarding a Christmas event, committee report for fall 1989, and the Big Thicket Hearing in the Senat
Urea‐injection and ‐preparation in Diesel applications, Multiphase multicomponent modeling using Star‐CD
No full textThe most promising approach to fulfill the Diesel engine´s future NOx‐emission limits is exhaust gas aftertreatment with the Selective Catalytic Reduction (SCR). The state‐of‐the‐art approach in automotive technology is the supply of a chemical reductant (ammonia) which is prepared from a Urea‐Water‐solution spray inserted into the exhaust gas upstream of an SCR‐catalyst.
At the Institute For Powertrains And Automotive Technology Star‐ CD was used to understand the complex process of ammonia preparation. The code has to deal with multiphase fluid dynamics in combination with multicomponent thermodynamics. We present the analysis of available submodels for the impingement of the multicomponent urea‐water‐spray on the hot walls of the exhaust pipes, focusing on liquid film formation and -dynamics. This includes the presentation of a solving strategy in Star‐CD to overcome the gap in timesteps of fast droplet dynamics and relatively slow liquid film dynamics. Moreover Star‐CD`s multicomponent droplet‐ and film‐evaporation capabilities to simulate the formation of vaporised ammonia from the urea‐water‐solution have been examined. The submodel for the complex phenomenon of liquid‐film‐boiling has been studied and evaluated in detail. In this context the role of modelling the thermal wall boundary condition via Conjugate Heat Transfer will be pointed out. The necessity of complex physical theorie
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