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.

Fixed mounted sorting cuvette with user replaceable nozzle

Abstract: A flow cell and flow cytometer in which a nozzle at the end of a flow channel is disposed on a removable substrate held at a registered location on a flow cell. Other elements including illumination optics, light collection optics, and the flow cell may then be positioned at fixed locations and would not require subsequent periodic adjustment. The registered location for positioning the nozzle allows removal and replacement of the nozzle key with the nozzle subsequently positioned in the identical location.

Mathematical Modeling and Experimental Verification of Stationary Waterjet Cleaning Process

Abstract: The use of stationary waterjet for the removal of coating material from the substrate is investigated analytically and experimentally. In the analysis, the cleaning width as a function of standoff distance, water pressure, and nozzle radius is derived by considering the structure of waterjet and the cleaning mechanism. Also derived are the relations of the optimal cleaning standoff distance and maximum cleaning width to the critical cleaning standoff distance, and how the water pressure and nozzle radius affect this critical standoff distance. These derived analytical relations are verified with experimental results.

Acoustics, Vortex Shedding, and Low-Frequency Dynamics Interaction in an Unstable Hybrid Rocket

Abstract: This paper deals with an experimental investigation into the stability behavior of a hybrid rocket where gaseous oxygen is fed with either an axial conical subsonic nozzle or a radial injector. The influence of the oxidizer-injection configurations on the motor stability is thoroughly examined. These distinct oxidizer-injection techniques allowed unveiling key and so far unreported features of the hybrid rocket combustion stability, especially emphasizing the role of vortex shedding which occurs in both the pre- and postcombustion chamber. Axial and radial injectors caused completely stable and unstable combustor operations, respectively, and this fact has been attributed to the fluid dynamics and unsteady heat release at the entrance of the fuel grain port. In particular, the unstable combustion in the radial-flow injector motor was dominated by low-frequency pressure oscillations, around 10-20 Hz. These low-frequency pressure oscillations were always accompanied by longitudinal acoustic modes. In some cases, the pressure oscillations abruptly increased, reaching peak-to-peak amplitude close to 70% of the mean chamber pressure, which is somewhat unusual for hybrid engines. Vortex shedding in the aft-mixing chamber is considered as the main driving mechanism of this latter behavior.

Cleaning exhaust gases from combustion installations

Abstract: In a process for cleaning the exhaust gases from combustion installations, a dilute urea solution prepared in a reagent tank (20) is introduced into the hot exhaust gas flow (30) of differing concentrations and is finely sprayed in the direction of the exhaust gas flow. After decomposition of the urea in a pyrolysation channel (14), the exhaust gas flow (30) is homogeneously mixed in-line by a mixer located in a mixing channel (16). In a subsequent in-line reaction channel (18), the reducible exhaust gas constituents are converted into non-toxic gases in at least one selective reduction catalyst which does not contain zeolite (36), then, dependent on the installation, the oxidizable exhaust gas components are converted into non-toxic gases without reagent in at least one oxidation catalyst (38) to produce a virtually complete reaction. A dual substance nozzle appliance (26) opening into the pyrolysation channel (14) comprises a reversing valve (88) for the working and blowing out position, a casing tube (24) for the compressed air, located in the area of the exhaust gas flow ( 30), a urea conductor carried at a distance in the casing tube (24) and a nozzle for fine spraying of the dilute urea solution.

Intense, hyperthermal source of organic radicals for matrix-isolation spectroscopy

Abstract: We have incorporated a pulsed, hyperthermal nozzle with a cryostat to study the matrix-isolated infrared spectroscopy of organic radicals. The radicals are produced by pyrolysis in a heated, narrow-bore (1-mm-diam) SiC tube and then expanded into the cryostat vacuum chamber. The combination of high nozzle temperature (up to 1800 K) and near-sonic flow velocities (on the order of 104 cm s−1) through the length of the 2 cm tube allows for high yield of radicals (approximately 1013 radicals pulse−1) and low residence time (on the order of 10 μs) in the nozzle. We have used this hyperthermal nozzle/matrix isolation experiment to observe the IR spectra of complex radicals such as allyl radical (CH2CHCH2), phenyl radical (C6H5), and methylperoxyl radical (CH3OO). IR spectra of samples produced with a hyperthermal nozzle are remarkably clean and relatively free of interfering radical chemistry. By monitoring the unimolecular thermal decomposition of allyl ethyl ether in the nozzle using matrix IR spectroscopy, we have derived the residence time (τnozzle) of the gas pulse in the nozzle to be around 30 μs.