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ABSTRACT
The present paper considers hybrid-linked jet impingement, which involves both parallel linked jets and series linked jets. An optimization platform was established with the aid of computational fluid dynamics, response surface methodology, and genetic algorithm. Of particular interest is the influence of optimization strategies and constrain conditions on the results. With the objective function of minimal mass flow rate, the optimal structures show consistent parameters and series linked topology. On the contrary, the results for minimal pressure drop show different topologies under different constraint conditions. Such results indicate the capability of hybrid-linked jet impingement to fit a wide range of applications by changing the topology.
Nomenclature
| A | = | area, m2 |
| Ch | = | regression coefficient for heat transfer |
| Cp | = | regression coefficient for pressure drop |
| Dj | = | impingement hole diameter, mm |
| h | = | heat transfer coefficient, W/m2K |
| k | = | thermal conductivity, W/mK |
| L | = | thickness of the horizontal jet plate, mm |
| m | = | mass flow rate, kg/s |
| n | = | jet number |
| np | = | number of input parameters for the CCD method |
| nc | = | central points for the CCD method |
| N | = | number of cases in the test matrix |
| Nu | = | Nusselt number |
| Nucon | = | heat transfer coefficient constrains |
| Px | = | jet hole pitch in stream-wise direction, mm |
| Py | = | jet hole pitch in span-wise direction, mm |
| Pz | = | distance from the jet exit to the target wall, mm |
| p | = | pressure, Pa |
| pt,i | = | inlet total pressure, Pa |
| po | = | outlet static pressure, Pa |
| p* | = | pressure normalized by outlet pressure |
| p* | = | pressure constrains |
| RD | = | jet diameter ratio |
| Re | = | Reynolds number |
| u | = | velocity, m/s |
| t | = | thickness of the vertical jet plate, mm |
| T | = | temperature, K |
| Tc | = | coolant inlet temperature, K |
| Tw | = | wall temperature, K |
| wo | = | outlet slot width, mm |
| y+ | = | y plus value for turbulence modeling |
| Σ | = | topology parameter |
| ρ | = | density, kg/m3 |
| μ | = | dynamic viscosity, Pa · s |
| ε | = | logical value to determine location of jets |
Nomenclature
| A | = | area, m2 |
| Ch | = | regression coefficient for heat transfer |
| Cp | = | regression coefficient for pressure drop |
| Dj | = | impingement hole diameter, mm |
| h | = | heat transfer coefficient, W/m2K |
| k | = | thermal conductivity, W/mK |
| L | = | thickness of the horizontal jet plate, mm |
| m | = | mass flow rate, kg/s |
| n | = | jet number |
| np | = | number of input parameters for the CCD method |
| nc | = | central points for the CCD method |
| N | = | number of cases in the test matrix |
| Nu | = | Nusselt number |
| Nucon | = | heat transfer coefficient constrains |
| Px | = | jet hole pitch in stream-wise direction, mm |
| Py | = | jet hole pitch in span-wise direction, mm |
| Pz | = | distance from the jet exit to the target wall, mm |
| p | = | pressure, Pa |
| pt,i | = | inlet total pressure, Pa |
| po | = | outlet static pressure, Pa |
| p* | = | pressure normalized by outlet pressure |
| p* | = | pressure constrains |
| RD | = | jet diameter ratio |
| Re | = | Reynolds number |
| u | = | velocity, m/s |
| t | = | thickness of the vertical jet plate, mm |
| T | = | temperature, K |
| Tc | = | coolant inlet temperature, K |
| Tw | = | wall temperature, K |
| wo | = | outlet slot width, mm |
| y+ | = | y plus value for turbulence modeling |
| Σ | = | topology parameter |
| ρ | = | density, kg/m3 |
| μ | = | dynamic viscosity, Pa · s |
| ε | = | logical value to determine location of jets |
Acknowledgments
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