# Additive Manufacturing and Chemical Engineering: Looking for Synergies from a Bibliometric Study
## 4 Review of Research Focused on Additive Manufacturing and Chemical Engineering
### Additive Manufacturing and Chemical Engineering: Future Needs
#### 4.2.3 Additive Manufacturing and Heat Exchange  
Additive manufacturing emerges as a promising alternative in the production of more efficient and compact heat exchangers. The design freedom offered by additive manufacturing allows for process optimization, control of surface roughness, and the use of compatible materials, all of them key aspects for technical viability and economic competitiveness [147]. Additive manufacturing also offers the possibility to create heat exchangers  
Figure 15: Examples of applications of topology optimization and generative design in chemical engineering: (**A**) topologically optimized design of microchannel heat sinks with the schematic images of the microstructure for three different values of the design variable \(\epsilon\), including streamlines from the uniform flow velocity inlet to the uniform pressure outlet and the temperature map of the coolant (Reprinted with permission from Ref [144]. 2021, Elsevier); (**B**) optimization results under coupled thermal loads for integrated thermal protection systems for different N values, a weight factor being introduced to balance thermal and mechanical constraints (Reprinted with permission from Ref [145]. 2019, Elsevier); (**C**) evolution of the optimal internal fin shapes for laminar and turbulent conditions at different generations under forced internal single-phase flow (Reprinted with permission from Ref [146]. 2021, Elsevier). with more complex geometries, maximizing the area-volume ratio to enhance heat transfer efficiency. This capability for advanced design enables adaptation to challenging operating environments, such as high pressures and corrosive media. Additionally, the short lead time for the production and customization of heat exchangers through additive manufacturing brings additional benefits, including weight reduction, consolidation of components, and space optimization, facilitating the implementation of new design concepts in shorter time periods [148]. Specific studies have demonstrated the viability of additive manufacturing in the fabrication of heat exchangers for a range of applications. One study compared the performance of traditionally manufactured heat exchangers (oil coolers for aircraft) to the ones produced using an additive manufacturing technology (Direct Metal Laser Sintering), demonstrating increased heat transfer efficiency for the models obtained by additive manufacturing (Figure 16a,b) [149]. Another study presented a microchannel heat exchanger manufactured via Direct Metal Laser Sintering too (Figure 16c), showing significant improvements in heat transfer density compared to conventional plate heat exchangers [150]. Finally, a study investigated the use of porous lattice structures fabricated through Selective Laser Melting to enhance heat transfer in air-to-air heat exchangers (Figure 16d). The results demonstrated increased thermal conductivity and heat transfer coefficient compared to conventional fin tube heat exchangers [151]. Although additive manufacturing technologies surpass conventional techniques in producing complex geometries, their relatively poor final outcome can be leveraged favorably under specific outcomes. Currently, additive manufacturing does not completely replace conventional methods commercially but progresses alongside them, demonstrating its benefits. Continuous advancements in additive manufacturing will position it as  
Figure 16: Examples of heat exchangers produced by additive manufacturing: (**a**) additively manufactured aircraft oil cooler attached to build plate with supports and (**b**) comparison to the traditionally built model (Reprinted with permission from Ref [149]. 2018, Elsevier); (**c**) zoom-in section view of the hot-side inclined fins and the cold-side inclined manifold wall for an additively manufactured heat exchanger core, including the small sectional coupon (Reprinted with permission from Ref [150].