Abo Bibliothek: Guest

ISSN Online: 2377-424X

ISBN Print: 978-1-56700-474-8

ISBN Online: 978-1-56700-473-1

International Heat Transfer Conference 16
August, 10-15, 2018, Beijing, China

DIRECT NUMERICAL SIMULATION OF TURBULENT HEAT TRANSFER IN PULSATING PLANE CHANNEL FLOWS WITH DIFFERENT FREQUENCY

Get access (open in a dialog) DOI: 10.1615/IHTC16.cov.023774
pages 3573-3579

Abstrakt

For the design of fuel-efficient reciprocating engines, it is necessary to evaluate heat transfer loss from the engine cylinder under flow pulsation. Despite the complex turbulent flows induced by reciprocating piston in the engine cylinder, conventional standard k-epsilon models with a wall function are still often applied in engine development to save the computational cost under acceptable levels. The use of these conventional models under such complex turbulent flows may not be suitable to accurately evaluate the transient local heat loss on the inner surface of the cylinder. In this study, fundamental numerical analysis is performed to examine the validity of the model assumptions, such as analogy between the momentum and heat transfer and applicability of standard wall function, under the pulsating turbulent flow conditions. To this end, DNS (Direct Numerical Simulation) was conducted for turbulent convective heat transfer in the fully developed plane channel under mainstream pulsation with Womersley number Wo = 19.8, 28.0, 39.6 at the mean friction Reynolds number Reτs = 300. Phase-averaged mean velocity, friction Reynolds number and Nusselt number were obtained at each phase of the flow pulsation. As a result, it was found that the turbulence statistics changes compared to those of steady channel flow due to the flow pulsation. These results indicate advanced turbulence models or wall functions are necessary for the better prediction of local heat transfer rate on the inner surface of the engine cylinders.