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Featured researches published by Dave Hanna.


Journal of Engineering for Gas Turbines and Power-transactions of The Asme | 2014

Steady State Engine Test Demonstration of Performance Improvement With an Advanced Turbocharger

Harold Sun; Dave Hanna; Liangjun Hu; Eric Warren Curtis; James Yi; Jimi Tjong

Heavy EGR required on diesel engines for future emission regulation compliance has posed a big challenge to conventional turbocharger technology for high efficiency and wide operation range. This study, as part of the U.S. Department of Energy sponsored research program, is focused on advanced turbocharger technologies that can improve turbocharger efficiency on customer driving cycles while extending the operation range significantly, compared to a production turbocharger. The production turbocharger for a medium-duty truck application was selected as a donor turbo. Design optimizations were focused on the compressor impeller and turbine wheel. On the compressor side, advanced impeller design with arbitrary surface can improve the efficiency and surge margin at the low end while extending the flow capacity, while a so-called active casing treatment can provide additional operation range extension without compromising compressor efficiency. On the turbine side, mixed flow turbine technology was revisited with renewed interest due to its performance characteristics, i.e., high efficiency at low-speed ratio, relative to the base conventional radial flow turbine, which is relevant to heavy EGR operation for future diesel applications. The engine dynamometer test shows that the advanced turbocharger technology enables over 3% BSFC improvement at part-load as well as full-load condition, in addition to an increase in rated power. The performance improvement demonstrated on an engine dynamometer seems to be more than what would typically be translated from the turbocharger flow bench data, indicating that mixed flow turbine may provide additional performance benefits under pulsed exhaust flow on an internal combustion engine and in the low-speed ratio areas that are typically not covered by steady state flow bench tests.


Volume 1B: Marine; Microturbines, Turbochargers and Small Turbomachines; Steam Turbines | 2014

An Engine System Approach to Improve Turbocharger Fatigue Life

Harold Sun; Liangjun Hu; Jizhong Zhang; Waheed Alashe; Dave Hanna; Eric Warren Curtis; James Yi

The ultimate goal of an advanced turbocharger development is to have a superior aerodynamic performance while having the turbocharger survive various real world customer applications. Due to the uncertainty of customer usage and driving pattern, the fatigue life prediction is considered one of the most ambiguous analyses in the entire design and analyses processes of the turbocharger. The turbocharger system may have various resonant frequencies, which may be within the range of turbocharger operation for automotive applications. A turbocharger may operate with excessive stresses when running near resonant frequencies. The turbocharger may experience fatigue failures if the accumulative cycles of the turbocharger running across the resonant frequencies exceeds a certain limit.In this study, the authors propose an alternative approach to mitigate this kind of fatigue issues: i.e. engine system approach to improve turbocharger fatigue life via avoiding operating the turbocharger near resonant speeds for extended period of time. A preliminary numerical study was made and presented in this paper to assess the feasibility of such an engine system approach, which is followed by an engine dynamometer test for engine performance sensitivity evaluation when the turbocharger operation condition was adjusted to improve the high cycle fatigue life. The study shows that for a modern diesel engine equipped with electrically controlled variable geometry turbine and EGR for emission control, through the engine calibration and control upgrade, turbocharger operation speed can be altered to stay away from certain critical speeds if necessary.The combined 1D and 3D numerical simulation shows the bandwidth of the turbine “risk zone” near one of the resonant speeds and the potential impact on engine performances if the turbocharger speed has to be shifted out of the “risk zone.”© 2014 ASME


Archive | 2012

CONTROL STRATEGY FOR DECREASING RESONANCE IN A TURBOCHARGER

Harold Sun; Yong Shu; Dave Hanna; Tim Schram


Archive | 2011

Sliding vane geometry turbines

Harold Sun; Jizhong Zhang; Liangjun Hu; Dave Hanna


Volume 8: Microturbines, Turbochargers and Small Turbomachines; Steam Turbines | 2016

Acoustic Measurements From an Automotive Centrifugal Compressor With a Switchable Dual-Port Casing Treatment for Extended Operating Range

Rick Dehner; Ahmet Selamet; Michael Steiger; Harold Sun; Dave Hanna; Liangjun Hu


Archive | 2013

VARIABLE GEOMETRY TURBINE VANE

Harold Sun; Liangjun Hu; Ben Zhao; Dave Hanna


Global Powertrain Congress 2009, GPC 2009 Troy | 2009

Challenges and opportunities in turbocharger technology for future diesel LTC

Harold Sun; Dave Hanna; Eric Krivitzky; Louis M. Larosiliere; Nick Baines; Ron Forni; Liangjun Hu; Jizhong Zhang; Ming Chia Lai


Archive | 2015

Variable geometric turbine and nozzle wheel blades of same

Dave Hanna; Harold Sun; Ben Zhao; Liangjun Hu


Archive | 2015

Metallblech-Turbinengehäuse mit Zellenstruktur-Verstärkung Sheet metal turbine housing with cell structure reinforcement

Harold Sun; Leon Hu; Dave Hanna


Archive | 2015

Metallblech-Turbinengehäuse mit Zellenstruktur-Verstärkung

Harold Sun; Leon Hu; Dave Hanna

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