Nozzle

About: Nozzle is a research topic. Over the lifetime, 158675 publications have been published within this topic receiving 893026 citations. The topic is also known as: spout.

High mass throughput particle generation using multiple nozzle spraying

Abstract: Spraying apparatus and methods that employ multiple nozzle structures for producing multiple sprays of particles, e.g., nanoparticles, for various applications, e.g., pharmaceuticals, are provided. For example, an electrospray dispensing device may include a plurality of nozzle structures, wherein each nozzle structure is separated from adjacent nozzle structures by an internozzle distance. Sprays of particles are established from the nozzle structures by creating a nonuniform electrical field between the nozzle structures and an electrode electrically isolated therefrom.

Variable geometry turbine

Abstract: A turbocharger variable geometry turbine of the type which includes nozzle vanes displaceable across the turbine inlet flow path into slots. The vanes have cut-outs which reduce the vane cord and permit peak turbine efficiency over a range of geometries.

The Use of an Ejector as a Refrigerant Expander

Abstract: One of the thermodynamic losses in the vapor-compression retr1geration cycle is the throttllng process in the expansion valve. It work is extracted from the refr1gerant during the expansion process, the efficiency of the cycle is swnificantly 1mproved. It 1s proposed that the high-pressure retngerant be used as the motive fluid of a Jet ejector. Instead of extract1ng mechanical work from the expanding refrigerant, 1ts kinetic energy is used to partially compress the saturated vapor leaving the evaporator, increas1ng the enthalpy change in the evaporator and reduc1ng the load on the compressor. A first-order analysis of the cycle performance shows sign1ficant 1ncrease in coeffic1ent of performance and decrease 1n compressor displacement relative to a standard vapor-compresslon cycle. The analysis shows much greater performance changes tor some refrigerants than for others, 1ndicating a potential impact on the selection of new, non-CFC refrigerants. COP h p r s u X q Coetficlent of Performance specific enthalpy pressure motive flow/total flow specific entropy veloc1ty qua.l1ty efficiency IIOIIENCLATURE d tc ge m n s Subscripts: diffuser outlet condenser saturated l1quid evaporator saturated vapor mixing section outlet motive nozzle outlet suction nozzle outlet

Numerical Characterization of Particle Beam Collimation: Part II Integrated Aerodynamic-Lens-Nozzle System

Abstract: As a sequel to our previous effort on the modeling of particle motion through a single lens or nozzle, flows of gas–particle suspensions through an integrated aerodynamic-lens–nozzle inlet have been investigated numerically. It is found that the inlet transmission efficiency (ηt) is unity for particles of intermediate diameters (Dp ∼ 30–500 nm). The transmission efficiency gradually diminishes to ∼40% for large particles (Dp > 2500 nm) because of impact losses on the surface of the first lens. There is a catastrophic reduction of ηt to almost zero for very small particles (Dp ≤ 15 nm) because these particles faithfully follow the final gas expansion. We found that, for very small particles, particle transmission is mainly controlled by nozzle geometry and operating conditions. A lower upstream pressure or a small inlet can be used to improve transmission of very small particles, but at the expense of sampling rate, or vice versa. Brownian motion exacerbates the catastrophic reduction in ηt for small parti...

Vortex flow and cavitation in diesel injector nozzles

Abstract: Flow visualization as well as three-dimensional cavitating flow simulations have been employed for characterizing the formation of cavitation inside transparent replicas of fuel injector valves used in low-speed two-stroke diesel engines. The designs tested have incorporated five-hole nozzles with cylindrical as well as tapered holes operating at different fixed needle lift positions. High-speed images have revealed the formation of an unsteady vapour structure upstream of the injection holes inside the nozzle volume, which is referred to as ‘string-cavitation’. Computation of the flow distribution and combination with three-dimensional reconstruction of the location of the strings inside the nozzle volume has revealed that strings are found at the core of recirculation zones; they originate either from pre-existing cavitation sites forming at sharp corners inside the nozzle where the pressure falls below the vapour pressure of the flowing liquid, or even from suction of outside air downstream of the hole exit. Processing of the acquired images has allowed estimation of the mean location and probability of appearance of the cavitating strings in the three-dimensional space as a function of needle lift, cavitation and Reynolds number. The frequency of appearance of the strings has been correlated with the Strouhal number of the vortices developing inside the sac volume; the latter has been found to be a function of needle lift and hole shape. The presence of strings has significantly affected the flow conditions at the nozzle exit, influencing the injected spray. The cavitation structures formed inside the injection holes are significantly altered by the presence of cavitation strings and are jointly responsible for up to 10% variation in the instantaneous fuel injection quantity. Extrapolation using model predictions for real-size injectors operating at realistic injection pressures indicates that cavitation strings are expected to appear within the time scales of typical injection events, implying significant hole-to-hole and cycle-to-cycle variations during the corresponding spray development.