Entropy generation in a diesel engine turbocharging system
| Autor: | K. Nakonieczny |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
Valve timing
Exergy Engineering Wastegate Entropy production business.industry Mechanical Engineering Mechanical engineering Building and Construction Diesel engine Pollution Industrial and Manufacturing Engineering General Energy Control theory Electrical and Electronic Engineering Intercooler business Gas compressor Civil and Structural Engineering Turbocharger |
| Zdroj: | Energy. 27:1027-1056 |
| ISSN: | 0360-5442 |
| DOI: | 10.1016/s0360-5442(02)00082-8 |
| Popis: | The paper describes a model of entropy production in a diesel engine turbocharging system, discussing the processes occurring in the compressor, turbine, piping system, charge-air cooler and valves with the exclusion of combustion. The charging efficiency of the system is studied in two distinct engine operating states, conforming to maximum torque and nominal power conditions. Unlike in the standard approach, where the irreversibilities are derived from the balance equation for exergy and thus are addressed inexactly, the criterion function based on the notion of entropy generation, introduced in this paper, improves second law analysis of turbocharged engines by accounting for a direct description of the system internal irreversibilities. This function is used for the examination of an impact of the system design parameters on its efficiency. Computations based on the unsteady one-dimensional flow model show that, under the variations of the inlet pipe length, the timings of inlet valve opening and exhaust valve closure, and the valve overlap period, a favourable correlation can be found between the decrease of entropy production and the increase in amount of air charged into the engine cylinders. The other variables under study, including the turbine equivalent area, temperature decrease in intercooler and wastegate effective area ratio, show an opposite correlation, and thus, can be viewed as constraints in the system optimisation. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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