A miniature steam ejector refrigeration system embedded with a capillary pump loop can result in a compact design which can be used for electronics cooling. In this paper, computational fluid dynamics (CFD) is employed to investigate the effects of the area ratio of the ejector constant-area mixing section to the nozzle throat, the length of the constant-area section, and the nozzle exit positi...

We present a three-dimensional Reynolds-averaged Navier–Stokes investigation of the impact on nozzle aerodynamic performance of deflector vanes used for noise suppression in separate-flow turbofan engines. The vanes are installed in the bypass duct and deflect the bypass plume downward relative to the core plume. This study considers a single pair of vanes, with a NACA 0012 airfoil section, ins...

We analyze a long-wavelength model of viscous entrainment from a nozzle and show that, when appropriate large-scale boundary conditions are imposed, the entrainment transition can become continuous. As the entrainment threshold is approached from above, the entrained steady-state spout becomes vanishingly thin compared to the nozzle radius and takes the form of a thin tendril emerging from a ba...

In the present work, the influence of a very early pilot injection on pollutant formation was investigated in a Common-Rail DI Diesel engine. The engine was operated at conventional part-load conditions at 2000 rpm, an EGR variation was done and the injected fuel mass was 15 mm^3/cycle. The Nozzle type were conical and flow optimized geometries (ks nozzle) with hole diameters of 0.141 mm, lengt...

This paper describes Nano-particle based Planar Laser Scattering (NPLS) flow visualization of angled supersonic jets into a supersonic cross flow based on the HYpersonic Low TEmperature (HYLTE) nozzle which was widely used in DF chemical laser. In order to investigate the non-reacting flowfield in the HYLTE nozzle, a testing section with windows was designed and manufactured. The impact of seco...

In this paper, we report a simple technique for the fabrication of planar valveless micropumps. The technique utilizes MEMS fabrication methods by using a double sided etch technique. Instead of using several masks and process steps, an anisotropic wet etch technique at both sides of a silicon substrate is implemented at the same time for creating the pump membrane and the diffuser/ nozzle elem...

Series of laboratory tests were carried out to study the extent of scour caused by a three-dimensional wall jets exiting from a square cross-section nozzle and into a non-cohesive sand beds. Previous observations have indicated that the effect of the tail water depth was significant for densimetric Froude number greater than ten. However, the present results indicate that the cut off value coul...

In this paper, we present our efforts to test experimentally and numerically the concept of bubble augmented jet propulsion. The numerical model is based on a two-way coupling between an Eulerian description of the flow field and a Lagrangian tracking of bubbles using the Surface Averaged Pressure (SAP) model. The numerical results compares favorably with nozzle experiments. A half 3-D nozzle f...

Nowadays, the environmental concern in machining industry is a fact. Because of that, in this article a new cooling-lubrication system which combines CO2 cryogenic and MQL technologies is presented. The aim of this new cooling-lubrication system is to offer an ecological and economic efficient alternative. Two nozzle adapters are proposed with different CO2 outlets. The developed nozzles are Pl...

This paper reports a novel actuating design that uses the shear deformation of a piezoelectric actuator to deflect a bulge-diaphragm for driving an array microdroplet ejector. In essence, we employed a circular-shaped actuator poled radial direction with remnant polarization normal to the actuating electric field for inducing the piezoelectric shear effect. The array microdroplet ejector consis...