@article{panse_ekkad_2021, title={A numerical parametric study to enhance thermal hydraulic performance of a novel alternating offset oblique microchannel}, volume={79}, ISSN={1040-7782 1521-0634}, url={http://dx.doi.org/10.1080/10407782.2021.1872259}, DOI={10.1080/10407782.2021.1872259}, abstractNote={Abstract A novel alternating offset oblique microchannel (AOOMC) is proposed aimed at enhancing the thermal–hydraulic performance (THP) in microchannels. 3-D, conjugate numerical simulations are carried out over a range of Reynolds number from 200 to 800. The effect of three geometric parameters, relative oblique channel width relative fin offset width and oblique angle on THP is evaluated. THP shows an increasing–decreasing trend with and increases with increase in and for the range tested. The optimal geometry, and showcases the highest THP of 2.41 at Re = 800 which is superior to other enhanced microchannel geometries from the literature.}, number={7}, journal={Numerical Heat Transfer, Part A: Applications}, publisher={Informa UK Limited}, author={Panse, Sanskar S. and Ekkad, Srinath V.}, year={2021}, month={Jan}, pages={489–512} }
 @article{rudragoudar_chhatija_panse_ekkad_2021, title={Effect of channel aspect ratio and fin geometry on fluid flow and heat transfer performance of sectional oblique fin microchannels}, ISSN={["1936-3958"]}, DOI={10.1109/ITherm51669.2021.9503250}, abstractNote={Single-pass micro-channel heat sinks (MCHS) with water as the working fluid have been shown to deliver large heat removal rates with marginal pressure drop penalty. MCHS, because of their high surface area to volume ratio, provide large heat transfer coefficients (HTC) not found in other macro-scale channels and have found applications in power electronic devices and aerospace heat exchangers. Micro-channels with sectional oblique fins in the same direction augment heat transfer by reinitializing the boundary layer at the leading edge of each fin, causing the flow to be in a developing state, resulting in improved thermal performance. A detailed numerical study has been carried out on oblique fin microchannel heat sinks (OMC) to investigate the impact of channel aspect ratio (AR) and fin-pitch to oblique channel width ratio (BETA) on heat transfer and fluid flow characteristics. OMC with an aspect ratio ranging from 0.25 to 1, followed by four BETA values between 4 and 8, have been tested. Results reveal that OMC with AR of 0.6 outperforms the other configurations. A trade-off has been established where taller fins, although providing higher heat transfer area, suffer from poor fin efficiency, significantly impacting Nusselt number. OMC with BETA up to 6 has been shown to have similar hydro-thermal performance. The existing interplay between increasing mean channel velocity and decreasing heat transfer area has been identified at large hydraulic diameters.}, journal={PROCEEDINGS OF THE TWENTIETH INTERSOCIETY CONFERENCE ON THERMAL AND THERMOMECHANICAL PHENOMENA IN ELECTRONIC SYSTEMS (ITHERM 2021)}, author={Rudragoudar, Vaibhav Anandkumar and Chhatija, Harish and Panse, Sanskar S. and Ekkad, Srinath}, year={2021}, pages={42–51} }
 @article{panse_ekkad_2021, title={Forced convection cooling of additively manufactured single and double layer enhanced microchannels}, volume={168}, ISSN={0017-9310}, url={http://dx.doi.org/10.1016/j.ijheatmasstransfer.2020.120881}, DOI={10.1016/j.ijheatmasstransfer.2020.120881}, abstractNote={Metal based additive manufacturing (AM) is gaining increasing attention in the thermal management community due to the ability to fabricate intricate internal cooling features with acceptable accuracy. The non-traditional designs possible with AM can be leveraged to fabricate enhanced microchannel geometries which allow removal of high heat fluxes from power electronic devices. This study thereby explores the marriage of additive manufacturing and microchannel cooling where microchannels are fabricated using Direct Metal Laser Sintering (DMLS). Microchannels arranged in single layer and double layer configurations are evaluated for their heat transfer and pressure drop performance over Reynolds number, based on channel hydraulic diameter, ranging from 200 - 900 with water as the coolant. The double layer microchannels present a more complex geometry, with two layers of microchannels stacked one on top of the other which promises improved thermal performance based on literature. Enhancement features in the form of periodic oblique and alternating oblique secondary channels, known to augment fluid mixing and disrupt boundary layer growth are incorporated in both configurations aimed at augmenting the overall performance. Seven AM microchannel geometries, three in single and four in double layer configurations are tested. AM parts analyzed for their surface roughness and dimensional accuracy exhibit high surface roughness and deviation from design intent dimensions. Straight microchannel, fabricated using conventional manufacturing where the channel walls exhibit lower roughness levels serves as the baseline case. Comparing the performance of straight microchannels fabricated via conventional and additive methods reveal roughness induced augmentation in heat transfer and pressure drop of about 10-15%. Incorporation of secondary flow channels results in enhanced thermal hydraulic performance in both single and double layer configurations. Microchannels ranked based on thermal-hydraulic performance show double layer microchannel featuring oblique secondary channels offering the best performance with ~60% higher performance than baseline. The findings from this study highlight the potential of AM in developing sophisticated microchannels.}, journal={International Journal of Heat and Mass Transfer}, publisher={Elsevier BV}, author={Panse, Sanskar S. and Ekkad, Srinath V.}, year={2021}, month={Apr}, pages={120881} }
 @article{rajamuthu_panse_ekkad_2021, title={Heat Transfer Enhancement Through Array Jet Impingement on Strategically Placed High Porosity High Pore-Density Thin Copper Foams}, volume={143}, ISSN={1043-7398 1528-9044}, url={http://dx.doi.org/10.1115/1.4049173}, DOI={10.1115/1.4049173}, abstractNote={
 High porosity, high pore-density (pores per inch: PPI) metal foams are a popular choice in high heat flux cooling applications as they offer large heat transfer area over a given volume, however, accompanied by a concomitant increase in pumping power requirements. This experimental study aims toward developing a novel metal-foam based cooling configuration featuring thin copper foams (3 mm) subjected to orthogonal air jet array impingement. The foam configurations allowed strategic and selective placement of high pore-density (90 PPI) and high porosity (∼96%) copper foam on the heated surface with respect to the jet array in the form of foam stripes aiming to enhance heat transfer and reduce pressure drop penalty. The thermal-hydraulic performance was evaluated over range of Reynolds numbers, jet-to-jet (x/dj, y/dj) and jet-to-target (z/dj) spacings and compared with a baseline smooth surface. The effect of pore density was further analyzed by studying 40 PPI copper foam and compared with corresponding 90 PPI foam arrangement. The thermal-hydraulic performance was found to be governed by combinational interaction of three major factors: heat transfer area, ease of jet penetration, and foam volume usage. Strategic placement of metal foam stripes allowed better utilization of the foam heat transfer area and available foam volume by aiding penetration of coolant fluid through available foam thickness, thus performing better than the case where entire heat transfer area was covered with foam. For a fixed pumping power of 10 W, the optimal metal foam-jet configuration showed ∼50% higher heat transfer with negligible increase in pumping power requirements.}, number={3}, journal={Journal of Electronic Packaging}, publisher={ASME International}, author={Rajamuthu, Varun Prasanna and Panse, Sanskar S. and Ekkad, Srinath}, year={2021}, month={Jan} }
 @article{panse_singh_ekkad_2019, title={Thermal hydraulic performance augmentation by high-porosity thin aluminum foams placed in high aspect ratio ducts}, volume={161}, ISSN={1359-4311}, url={http://dx.doi.org/10.1016/j.applthermaleng.2019.114162}, DOI={10.1016/j.applthermaleng.2019.114162}, abstractNote={High porosity metal foams are known for providing high heat transfer rates, however, the concomitant higher-pressure losses have been a concern towards the realization of enhanced thermal hydraulic performance. Present study aims towards developing metal foam-based cooling configurations subjected to forced convection in a channel by employed very thin and high porosity Aluminum foams, where the goal is to achieve maximum foam volume participation in heat dissipation. To this end, a comprehensive experimental study has been carried out to investigate the effect of foam pore density (pores per inch: PPI) and channel aspect ratio (AR) on the thermal hydraulic performance of thin metal foams. High porosity (93%) thin aluminum foams with pore densities of 5, 20 and 40 PPI were studied, where the convective heat transport was facilitated through air forced through the channel. For the 40 ppi foams, three foam heights of 3.175 mm, 6.35 mm and 19 mm were tested, for 20 ppi foams, two foam heights of 6.35 mm and 19 mm were tested, and for the 5 ppi foams, one height of 19 mm was tested. These three different foam heights yielded in channel ARs of 16:1, 8:1 and 8:3, respectively. Heat transfer gain due to metal foams was evaluated against a geometrically identical smooth channel as well as with the Dittus-Boelter correlation for developed turbulent flow in circular ducts. Experimental data reveals that, for a given AR, an increase in pore-density resulted in both, increase in heat transfer as well as pressure drop. Amongst all three channel configurations, the 40 ppi foams had highest heat transfer, where the gain with respect to smooth channel for Re 5000 was ~21, 12 and 9.5 times, for 8:3, 8:1 and 16:1 channels respectively. Increase in channel AR (thinner foams) demonstrated an increase in heat transfer performance for a given pumping power. The thermal hydraulic trends observed for thin and high pore-density foams proved them to be viable candidates for compact electronics cooling.}, journal={Applied Thermal Engineering}, publisher={Elsevier BV}, author={Panse, Sanskar S. and Singh, Prashant and Ekkad, Srinath V.}, year={2019}, month={Oct}, pages={114162} }