【作者】

Ian Calvert，Ben McCully

【摘要】

论文已在中国上海举行的2013年CIMAC大会上发表。论文的版权归CIMAC所有。 General Electric Gas Engines division has established a product line centered on very high efficiency and specific output due to industry leading two-stage turbocharging, lean burn combustion strategy and Miller valve timing in combination. This on-going strategy to continually increase engine efficiency has pushed engine development to higher peak firing pressures and thermal loads on key components. This continuous efficiency increase is demanded with the proviso of maintaining or improving product reliability, robustness, availability, unit price and the associated life cycle costs. To meet these demands, the engineering team at GE Jenbacher, has been continuously developing new technologies and new design & analysis methodologies in conjunction with Ricardo Consulting Engineers. This paper provides an overview of the methodologies applied to the design, analysis and development of a new cylinder head as part of the overall development program for the recently released two-stage 624 engine into the GE Jenbacher gas engine portfolio. The design methodologies developed and applied over the course of the cylinder head development have at their foundations the core tools and methodologies used throughout all General Electric engineering departments, namely DFSS DFR etc. Experience gathered within the existing GE Jenbacher customer fleet over hundreds of thousands of engine operating hours combined with the broad variety of customer operating conditions have been at the core of developing accurate reliability models down to the component level.This data has been further analysed through the use of Design for Reliability (DFR) tools and processes to allow clear failure mode identification and determination of key failure mode accelerating factors. This is key in predicting the response of current components placed under new boundary conditions, ie higher pressures and temperatures. Single cylinder testing has been used to gather the detailed component operational data to allow this correlation to occur. These factors have then been used as assessment criteria within the design and analysis of the new cylinder head. The new cylinder head assembly is a design that incorporates both a different material, a new head structure and with a new water jacket design that includes cooled exhaust valve seats. The new cylinder head assembly has been subjected to an extensive design and analysis optimisation process involving multiple iterative FEA and CFD loops, full conjugate heat transfer analysis and a number of breakout studies to examine the detail of certain components within the assembly Confidence in the analysis methodologies has been further increased by extensive single cylinder testing of the current production cylinder head. This allowed a closed loop correlation process to be established in order to increase accuracy of the analytical approach and thereby allow the design of the new cylinder head to progress with high confidence. Specific accelerated tests were developed for the full sized development engines in order to confirm reliability predictions on both the baseline and newly developed cylinder head.These tests incorporated the key accelerating factors identified from the previous SCE work, and were successful in initiating predicted failures on the original head. The same tests were then used to demonstrate the robustness of the new cylinder head when placed under the same test conditions.

【会议名称】

第27届CIMAC会议

【会议地点】

上海

【下载次数】

2

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