A new design concept is presented to increase the adiabatic effectiveness of film cooling from a row of film-cooling holes. Instead of shaping the geometry of each hole; placing tabs, struts, or vortex generators in each hole; or creating a trench about a row of holes, this study proposes a geometry modification upstream of the holes to modify the approaching boundary-layer flow and its interaction with the film-cooling jets. Computations, based on the ensemble-averaged Navier–Stokes equations closed by the realizable k‐ε turbulence model, were used to examine the usefulness of making the surface just upstream of a row of film-cooling holes into a ramp with a backward-facing step. The effects of the following parameters were investigated: angle of the ramp (8.5deg, 10deg, 14deg), distance between the backward-facing step and the row of film-cooling holes (0.5D,D), blowing ratio (0.36, 0.49, 0.56, 0.98), and “sharpness” of the ramp at the corners. Results obtained show that an upstream ramp with a backward-facing step can greatly increase surface adiabatic effectiveness. The laterally averaged adiabatic effectiveness with a ramp can be two or more times higher than without the ramp by increasing upstream and lateral spreading of the coolant.

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An embedded PZT actuated peristaltic micropump that is a part of an implantable medical drug delivery system was designed and fabricated using Microelectromechanical Systems (MEMS) technology. Three embedded PZT actuators drive the three micropump chambers in a peristaltic motion. Static deflection data of the micropump chamber actuated by the PZT was measured using Atomic Force Microscope (AFM). The deflection data are linear below 90 volts and initiate a slightly non-linear behavior above 90 volts to 130 volts that is the maximum voltage we drive our micropump. In order to obtain linear response between driving voltage and pumping performance, it is recommended to drive the embedded PZT to actuate the peristaltic micropump below 90 volts. Volumetric flowrate and maximum pumping pressure data of the peristaltic micropump for four different driving frequencies (0.5 Hz, 1 Hz, 2 Hz, and 4 Hz) at 90 volts were tested. Volumetric flowrate and maximum pumping pressure data ofthe peristaltic micropump for four different driving frequencies (0.5 Hz, 1 Hz, 2 Hz, and 4 Hz) at 130 volts were tested. The overall efficiency of the micropump for two driving voltages (90 volts and 130 volts) was calculated. For a volumetric flowrate of 6 pL/min, the "erall efftleieney for the

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Computations, based on the Fluent-UNS code with second-order upwind differencing and the realizable k-~ model, were perfoll~led to study the flow and heat transfer over twodimensional (2-D) roughness geometries that resolve the details of the jagged surface. Parameters studied include height of approaching boundary layer to average roughness height (4.37mm to 42.77mm) for the same rough surface and eight different rough surfaces with the same approaching boundary layer in which the average roughness height, ll~ls, skewness, and kurtosis of the roughness vary in the ranges of 0.748 mm to 1.480 mm, 0.991 mm to 1.709 mm,-1.509 to 0.356, and 1.927 to 3.136, respectively. Results are presented for the contributions to the friction coefficient from shear and from pressure-locally and averaged over the entire rough surface. Also presented are the computed flow fields and the averaged Stanton numbers for all rough surfaces studied. Results obtained by the 2-D roughness-resolved simulations were compared with experimental data.