@inproceedings{KowalskiBarteltMcElwaine2007, author = {Kowalski, Julia and Bartelt, Perry and McElwaine, J.}, title = {Two-phase debris flow modeling}, series = {Geophysical Research Abstracts}, booktitle = {Geophysical Research Abstracts}, year = {2007}, language = {en} } @inproceedings{KowalskiBugnion2009, author = {Kowalski, Julia and Bugnion, Louis}, title = {An extended shallow flow theory for natural debris flows}, volume = {41}, number = {7}, pages = {609 -- 609}, year = {2009}, language = {de} } @article{KowalskiLinderZierkeetal.2016, author = {Kowalski, Julia and Linder, Peter and Zierke, S. and Wulfen, B. van and Clemens, J. and Konstantinidis, K. and Ameres, G. and Hoffmann, R. and Mikucki, J. and Tulaczyk, S. and Funke, O. and Blandfort, D. and Espe, Clemens and Feldmann, Marco and Francke, Gero and Hiecker, S. and Plescher, Engelbert and Sch{\"o}ngarth, Sarah and Dachwald, Bernd and Digel, Ilya and Artmann, Gerhard and Eliseev, D. and Heinen, D. and Scholz, F. and Wiebusch, C. and Macht, S. and Bestmann, U. and Reineking, T. and Zetzsche, C. and Schill, K. and F{\"o}rstner, R. and Niedermeier, H. and Szumski, A. and Eissfeller, B. and Naumann, U. and Helbing, K.}, title = {Navigation technology for exploration of glacier ice with maneuverable melting probes}, series = {Cold Regions Science and Technology}, journal = {Cold Regions Science and Technology}, number = {123}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0165-232X}, doi = {10.1016/j.coldregions.2015.11.006}, pages = {53 -- 70}, year = {2016}, abstract = {The Saturnian moon Enceladus with its extensive water bodies underneath a thick ice sheet cover is a potential candidate for extraterrestrial life. Direct exploration of such extraterrestrial aquatic ecosystems requires advanced access and sampling technologies with a high level of autonomy. A new technological approach has been developed as part of the collaborative research project Enceladus Explorer (EnEx). The concept is based upon a minimally invasive melting probe called the IceMole. The force-regulated, heater-controlled IceMole is able to travel along a curved trajectory as well as upwards. Hence, it allows maneuvers which may be necessary for obstacle avoidance or target selection. Maneuverability, however, necessitates a sophisticated on-board navigation system capable of autonomous operations. The development of such a navigational system has been the focal part of the EnEx project. The original IceMole has been further developed to include relative positioning based on in-ice attitude determination, acoustic positioning, ultrasonic obstacle and target detection integrated through a high-level sensor fusion. This paper describes the EnEx technology and discusses implications for an actual extraterrestrial mission concept.}, language = {en} } @inproceedings{KowalskiMcArdellBartelt2006, author = {Kowalski, Julia and McArdell, B. W. and Bartelt, Perry}, title = {A comparison of two approaches to modeling multiphase gravity currents}, series = {Geophysical Research Abstracts}, volume = {8}, booktitle = {Geophysical Research Abstracts}, year = {2006}, language = {en} } @inproceedings{KowalskiMcElwaine2008, author = {Kowalski, Julia and McElwaine, J.}, title = {Two-phase debris flow modeling}, series = {Geophysical Research Abstracts}, booktitle = {Geophysical Research Abstracts}, year = {2008}, language = {en} } @article{KowalskiMcElwaine2013, author = {Kowalski, Julia and McElwaine, Jim N.}, title = {Shallow two-component gravity-driven flows with vertical variation}, series = {Journal of Fluid Mechanics}, volume = {714}, journal = {Journal of Fluid Mechanics}, publisher = {Cambridge Univ. Press}, address = {Cambridge}, isbn = {0022-1120}, pages = {434 -- 462}, year = {2013}, language = {en} } @inproceedings{KreyerEsch2017, author = {Kreyer, J{\"o}rg and Esch, Thomas}, title = {Simulation Tool for Predictive Control Strategies for an ORCSystem in Heavy Duty Vehicles}, series = {European GT Conference 2017}, booktitle = {European GT Conference 2017}, pages = {16 Seiten}, year = {2017}, abstract = {Scientific questions - How can a non-stationary heat offering in the commercial vehicle be used to reduce fuel consumption? - Which potentials offer route and environmental information among with predicted speed and load trajectories to increase the efficiency of a ORC-System? Methods - Desktop bound holistic simulation model for a heavy duty truck incl. an ORC System - Prediction of massflows, temperatures and mixture quality (AFR) of exhaust gas}, language = {en} } @article{KreyerMuellerEsch2020, author = {Kreyer, J{\"o}rg and M{\"u}ller, Marvin and Esch, Thomas}, title = {A Calculation Methodology for Predicting Exhaust Mass Flows and Exhaust Temperature Profiles for Heavy-Duty Vehicles}, series = {SAE International Journal of Commercial Vehicles}, volume = {13}, journal = {SAE International Journal of Commercial Vehicles}, number = {2}, publisher = {SAE International}, address = {Warrendale, Pa.}, issn = {1946-3928}, doi = {10.4271/02-13-02-0009}, pages = {129 -- 143}, year = {2020}, abstract = {The predictive control of commercial vehicle energy management systems, such as vehicle thermal management or waste heat recovery (WHR) systems, are discussed on the basis of information sources from the field of environment recognition and in combination with the determination of the vehicle system condition. In this article, a mathematical method for predicting the exhaust gas mass flow and the exhaust gas temperature is presented based on driving data of a heavy-duty vehicle. The prediction refers to the conditions of the exhaust gas at the inlet of the exhaust gas recirculation (EGR) cooler and at the outlet of the exhaust gas aftertreatment system (EAT). The heavy-duty vehicle was operated on the motorway to investigate the characteristic operational profile. In addition to the use of road gradient profile data, an evaluation of the continuously recorded distance signal, which represents the distance between the test vehicle and the road user ahead, is included in the prediction model. Using a Fourier analysis, the trajectory of the vehicle speed is determined for a defined prediction horizon. To verify the method, a holistic simulation model consisting of several hierarchically structured submodels has been developed. A map-based submodel of a combustion engine is used to determine the EGR and EAT exhaust gas mass flows and exhaust gas temperature profiles. All simulation results are validated on the basis of the recorded vehicle and environmental data. Deviations from the predicted values are analyzed and discussed.}, language = {en} } @inproceedings{KreyerMuellerEsch2020, author = {Kreyer, J{\"o}rg and M{\"u}ller, Marvin and Esch, Thomas}, title = {A Map-Based Model for the Determination of Fuel Consumption for Internal Combustion Engines as a Function of Flight Altitude}, publisher = {DGLR}, address = {Bonn}, doi = {10.25967/490162}, pages = {13 Seiten}, year = {2020}, abstract = {In addition to very high safety and reliability requirements, the design of internal combustion engines (ICE) in aviation focuses on economic efficiency. The objective must be to design the aircraft powertrain optimized for a specific flight mission with respect to fuel consumption and specific engine power. Against this background, expert tools provide valuable decision-making assistance for the customer. In this paper, a mathematical calculation model for the fuel consumption of aircraft ICE is presented. This model enables the derivation of fuel consumption maps for different engine configurations. Depending on the flight conditions and based on these maps, the current and the integrated fuel consumption for freely definable flight emissions is calculated. For that purpose, an interpolation method is used, that has been optimized for accuracy and calculation time. The mission boundary conditions flight altitude and power requirement of the ICE form the basis for this calculation. The mathematical fuel consumption model is embedded in a parent program. This parent program presents the simulated fuel consumption by means of an example flight mission for a representative airplane. The focus of the work is therefore on reproducing exact consumption data for flight operations. By use of the empirical approaches according to Gagg-Farrar [1] the power and fuel consumption as a function of the flight altitude are determined. To substantiate this approaches, a 1-D ICE model based on the multi-physical simulation tool GT-Suite® has been created. This 1-D engine model offers the possibility to analyze the filling and gas change processes, the internal combustion as well as heat and friction losses for an ICE under altitude environmental conditions. Performance measurements on a dynamometer at sea level for a naturally aspirated ICE with a displacement of 1211 ccm used in an aviation aircraft has been done to validate the 1-D ICE model. To check the plausibility of the empirical approaches with respect to the fuel consumption and performance adjustment for the flight altitude an analysis of the ICE efficiency chain of the 1-D engine model is done. In addition, a comparison of literature and manufacturer data with the simulation results is presented.}, language = {en} } @inproceedings{KronigerHorikawaFunkeetal.2021, author = {Kroniger, Daniel and Horikawa, Atsushi and Funke, Harald and Pf{\"a}ffle, Franziska}, title = {Numerical investigation of micromix hydrogen flames at different combustor pressure levels}, series = {The Proceedings of the International Conference on Power Engineering (ICOPE)}, booktitle = {The Proceedings of the International Conference on Power Engineering (ICOPE)}, doi = {10.1299/jsmeicope.2021.15.2021-0237}, pages = {4 Seiten}, year = {2021}, abstract = {This study investigates the influence of pressure on the temperature distribution of the micromix (MMX) hydrogen flame and the NOx emissions. A steady computational fluid dynamic (CFD) analysis is performed by simulating a reactive flow with a detailed chemical reaction model. The numerical analysis is validated based on experimental investigations. A quantitative correlation is parametrized based on the numerical results. We find, that the flame initiation point shifts with increasing pressure from anchoring behind a downstream located bluff body towards anchoring upstream at the hydrogen jet. The numerical NOx emissions trend regarding to a variation of pressure is in good agreement with the experimental results. The pressure has an impact on both, the residence time within the maximum temperature region and on the peak temperature itself. In conclusion, the numerical model proved to be adequate for future prototype design exploration studies targeting on improving the operating range.}, language = {en} }