Department of Mechanical Engineering
A 3-year PhD scholarship or a three year post doc position is available at Technical University of Denmark, at the Department of Mechanical Engineering from September 1, 2008.
Introduction
Detailed “understanding” of the piston ring performance in a large diesel engine is a prerequisite for specifying operating and design parameters so as to reduce friction and wear.
Background
In large two-stroke engines a major contributor to the overall frictional loss is situated in the interface between the piston ring and the cylinder liner. One of the major prerequisites for analyzing piston ring friction and wear is a detailed description of the lubrication situation in the interface. An important condition for describing the frictional behavior of a piston ring correctly is knowledge about the amount and distribution of lubricant. During one stroke the piston ring experiences both hydrodynamic, mixed and boundary lubrication.
In large two-stroke engines the cylinder oil is supplied at discrete locations on the cylinder liner at a specific rate at a certain time. The shifting in lubrication regimes and the non-uniform oil distribution opens for the possibility of starved conditions for the piston ring bearing. It is important to quantify the oil film characteristics as a function of the operating conditions. Several test apparatus’ are used to study the interaction between a piston ring and a cylinder liner.
The experimental results are used to verify theoretical findings regarding the influence from speed, number of piston rings, surface characteristics, lubrication oil type and supply flow etc.
The test equipment is developed as a part of an ongoing cooperative research project between MAN Diesel A/S and DTU. The present Ph.D. study will be a part of the EU-project, HERCULES-É¿, which is a cooperative project within the 7th Framework Program. The aim of the Ph.D. study is to analyze, develop and test low friction and wear bearing applications for piston rings in large two-stroke engines.
Requirements
Candidates for the PhD degree should have a master's degree in engineering or a similar degree with an academic level equivalent to the master's degree in engineering. Candidates with prior knowledge in machine elements, tribology and experimental work are preferred.
Candidates for the PhD degree are subject to academic approval, and the candidate will be enrolled in one of the general degree programmes of DTU. Information about the general requirements for enrolment and the general planning of the scholarship studies is included in the general rules of DTU, which may be obtained from the DTU website (http://www.dtu.dk/English/Research/PhD_programme.aspx) or by application to the PhD programme office at tel: +45 4525 1176 or +45 4525 1177. The salary and appointment terms are consistent with the current rules for PhD degree students.
Candidates for the Post doc position should have a PhD degree in mechanical engineering, or academic qualifications equivalent to the PhD degree in engineering and they should have demonstrated qualifications in tribology and/or contact mechanics. The salary and appointment terms are negotiated in accordance with the current collective agreement for Danish University faculty members.
All interested candidates irrespective of age, gender, race, religion or ethnic background are encouraged to apply.
For further information regarding the position, please contact Professor Peder Klit (klit@mek.dtu.dk / +45 4525 6267).
Please send your application in triplicate, including CV and documentation of educational degree to:
Professor Peder Klit
Att.: Secretary Bente Brask Andersen
Technical University of Denmark
Department of Mechanical Engineering
Nils Koppels Alle, Building 404
DK-2800 Kgs. Lyngby
Denmark.
