@article{owoyele_echekki_2017, title={Toward computationally efficient combustion DNS with complex fuels via principal component transport}, volume={21}, ISSN={["1741-3559"]}, url={http://dx.doi.org/10.1080/13647830.2017.1296976}, DOI={10.1080/13647830.2017.1296976}, abstractNote={We investigate the potential of accelerating chemistry integration during the direct numerical simulation (DNS) of complex fuels based on the transport equations of representative scalars that span the desired composition space using principal component analysis (PCA). The transport of principal components (PCs) can reduce the number of transported scalars and improve the spatial and temporal resolution requirements. The strategy is demonstrated using DNS of a premixed methane–air flame in a 2D vortical flow and is extended to the 3D geometry to demonstrate the resulting enhancement in the computational efficiency of PC transport. The PCs are derived from a priori PCA of the same composition space using DNS. This analysis is used to construct and tabulate the PCs’ chemical source terms in terms of the PCs using artificial neural networks (ANN). Comparison of DNS based on a full thermo-chemical state and DNS based on PC transport with six PCs shows excellent agreement even for terms that are not included in the PCA reduction. The transported PCs reproduce some of the salient features of strongly curved and strongly strained flames. The results also show a significant reduction of two orders of magnitude in the computational cost of the simulations, which enables an extension of the solution approach to 3D DNS under similar computational requirements.}, number={4}, journal={COMBUSTION THEORY AND MODELLING}, author={Owoyele, Opeoluwa and Echekki, Tarek}, year={2017}, pages={770–798} }
 @article{owoyele_ferguson_brendan t. o'connor_2015, title={Performance analysis of a thermoelectric cooler with a corrugated architecture}, volume={147}, ISSN={["1872-9118"]}, DOI={10.1016/j.apenergy.2015.01.132}, abstractNote={A thermoelectric (TE) cooler architecture is presented that employs thin film thermoelectric elements on a plastic substrate in a corrugated structure sandwiched between planar thermal interface plates. This design represents a hybrid of a conventional bulk TE device and an in-plane thin film TE design. This design is attractive as it may benefit from low cost thin-film processing in a roll-to-roll fashion onto low-cost plastics substrates while maintaining a cross-plane heat flux for large area applications and a geometry that assists in maintaining a significant temperature difference across the thermoelectric elements. First, the performance of a single thermocouple is analyzed and the effect of the parasitic heat loss through the plastic substrate is examined. The performance of an array of thermocouples is then considered and the effects of various geometric parameters are analyzed with particular focus on the packing density of thermoelectric legs. The results show that while the coefficient of performance (COP) is comparable to a conventional bulk element TE cooler, the cooling power density drops off dramatically with a decrease in stacking angle of the legs. A comparison is then made between the heat sink demands of the hybrid TE design and a conventional bulk TE device where it is found that the lower cooling power density of the hybrid TE results in a reduction of heat sink demands as compared to bulk TE modules. The modeled performance suggest that the hybrid TE device may be advantageous in low cooling power density applications over relatively large areas where the low-cost nature of the device is maximized and less elaborate heat sink designs work effectively, cumulatively improving cost competitiveness.}, journal={APPLIED ENERGY}, author={Owoyele, Opeoluwa and Ferguson, Scott and Brendan T. O'Connor}, year={2015}, month={Jun}, pages={184–191} }