Session: 40-07: Turbine Secondary Flows and Interactions II

Paper Number: 151614

Experimental Characterization of Heat Transfer and Fluid Dynamics in Pulsating Exhaust Flows 

This research aims to provide an empirical understanding of the transient fluid dynamics and their consequential impact on heat transfer augmentation in exhaust reciprocating systems.

The exhaust flow conditions are generated by a Transient Air System Rig (TASR), which controls the frequency and lift-off profile of active valve trains to create realistic pressure waveforms.

Subsequently, the heat transfer characteristics are measured on a straight heated pipe (HEAT-TRAP).

 

This experimental setup replicates two waste heat recovery scenarios: industrial power generation (restricted outlet) and heavy-duty propulsion (open-ended).

Additionally, we studied the flow dynamics inside HEAT-TRAP using a flow conditioning section equipped with fin and honeycomb straighteners. The non-dimensional heat transfer coefficient was found to be independent of pulsation amplitude in both scenarios tested. In the restricted outlet case, the measured Nusselt number augmentation has a non-linear concave relationship with frequency. The open-ended case showed a steady heat transfer coefficient across the range of frequency tested, due to the low amplitudes achievable in an inertia dominated flow regime. The flow conditioner generally had a detrimental effect on heat transfer augmentation, while also reducing the high-frequency content of the pulse waveform through HEAT-TRAP by up to 26%. The results show that the unconditioned, restricted flow case has the largest potential for augmentation, when the system is tuned to allow local flow reversal.

Presenting Author: Matei C. Ignuta-Ciuncanu Imperial College London

Presenting Author Biography: Matei is a PhD Candidate at Imperial College London.

Authors:

Matei C. Ignuta-Ciuncanu Imperial College London
Jordan Michael Imperial College London
Shuyang Qian Imperial College
Chris Noon Imperial College
Ricardo F. Martinez-Botas Imperial College Lodon