Compared to state-of-the-art heat exchangers, manifold-microchannel heat exchangers (MMHX) have shown superior heat removal density at moderate pressure drops. However, MMHX made of Ni-based superalloys or other tough-to-machine materials can be a challenge to fabricate using conventional fabrication methods, because of the inherently complex manifold microchannel geometry, as well as the required small feature sizes. In this study, a direct metal laser sintering (DMLS) additive manufacturing (AM) technique was used to fabricate the compact high-temperature MMHX reported here. The AM MMHX was fabricated as a single object, which significantly simplifies the fabrication process. In this work, three different AM machines were used to study the effect of laser power, powder size, and layer thickness on the fin and channel sizes of the fabricated MMHX. To evaluate the minimum wall thickness able to hold the design pressures, pressure containment tests were performed. As a result, a wall thickness of 0.3 mm was shown to withstand 340 kPa and be leakage-free. A detailed analysis of different printing orientations and their effect on the MMHX's design was also performed. Lastly, a 76×76×76 mm3 MMHX was successfully fabricated with fin thickness of 0.13 mm out of maraging steel. A second unit with dimensions of 94×87.6×94.4 mm3 was successfully fabricated with fin thickness of 0.22 mm out of Inconel 718. Details of the fabrication process and key takeaway results are discussed.
But this is a false premise. There is no trade-off between "saving the economy" and "saving lives" nor between "the economy" and "the environment": If we degrade our environment, we will harm our health and destroy our economy. The real trade-off we face is choosing between the joint preservation of these three valuable dimensions of human existence or all three degrading into irreparable loss. To make this reality more tangible for policy-makers, new ways of thinking are needed.A reckoning happened on April 7, 2020. On this day, half of the planet's governments, representing half of humanity, were in lock-down due to the COVID-19 pandemic. In doing so, these state representatives decided that health-connected to our environment-was superior to economic growth.This chapter asserts that human health and the environment form a nexus and the support system, that makes a Well-being Economy possible. After describing the health-environment nexus, we illustrate it with five areas that show these interconnections.
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