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The decay characteristics of rectangular and triangular jets issuing from convergent nozzles are studied experimentally. The rectangular nozzle is of aspect ratio (AR) 2 and the triangular nozzle is equilateral. The exit and inlet areas of aspect ratio 2 rectangular nozzle and equilateral triangular nozzle are maintained same and the nozzles are tested at NPR's 2 to 4 corresponding to the underexpansion levels of sonic jets. From the measured centerline pressure at nozzle pressure ratios 2, 3 and 4, it is observed that the triangle jet offers superior mixing properties compared to the rectangle jet. The triangular jet has a shorter core length than the rectangular jet at all pressure ratios. Also, the triangular jet showed better decay than the rectangular jet. The core length of both the jets increased with increasing pressure ratio. The present work demonstrates that the nozzle geometry has a significant impact on the sonic jet's mixing, as the triangular sonic jet is found to possess shorter core and it decays faster than the equivalent rectangular jet. [ABSTRACT FROM AUTHOR]

Venturi nozzle is the simplest method in generating microbubble (MB). However, direct relation between venturi geometry variation and generated bubbles properties namely, bubble mean diameter (BMD) and dissolved oxygen (DO) level remains ambiguous. Thus, this study investigates the effect of outlet angle variation, gas intake and water flowrate on the BMD and DO level. Visualization experiments were performed on six geometry variant of venturi nozzles with fixed inlet angle (19°) and outlet angle of 8°,10° and 12° for Venturi with air intake and 5°, 12° and 45° for Venturi without air intake condition. In addition, the venturi nozzles also tested in varied flowrate of 13, 33 and 66 litre per minute (LPM). As the results, with the increment of outlet angle, the BMD decreases while the DO level increases in all nozzles. The presence of air intake in the nozzles produces larger MBs. Furthermore, The BMD and DO level is proportional to the water flowrate. Overall, the varied geometry parameters induce a difference in BMD which affects the DO level. [ABSTRACT FROM AUTHOR]

The purpose of this work is to examine stream parameters in circuits of hypersonic facilities and to determine the degree of influence of non-equilibrium physical and chemical processes using numerical modeling of real gas flow and heat transfer. For numerical modeling, the work employs the well-known ANSYS Fluent software and the HSFlow program (development of TsAGI) supplemented by a physicochemical module. Axisymmetric Navier-Stokes equations for viscous heat-conducting gas are solved in combination with the equations of chemical kinetics and oscillatory mode energy relaxation. Calculations were performed for the flow field in the nozzles and test sections of two facilities: T-122M (without a model) and VAT-104 with a model of a cylinder in the test section. Results were compared with the results of calculations that employed a simplified model of real air properties where only equilibrium excitation of oscillatory degrees of freedom of oxygen and nitrogen molecules was considered. [ABSTRACT FROM AUTHOR]

Visualisation of compressible jet from converging nozzles with passive mixing enhancements has been done using an economical shadowgraph setup. A biconvex lens has been used to collimate light from an LED (point source) and the collimated beam is passed normal to the jet axis. A DSLR camera is used to capture the shock structures being visualized through shadowgraphy. The test nozzles have been designed with passive mixing enhancements, namely chevrons, which are shown to be effective in noise reduction by previous numerical studies as noted from literature survey. Nozzle A is a baseline nozzle with circular cross-section. Nozzle B is a 6-chevron nozzle. Nozzle C is a 6- chevron nozzle with a comparatively thinner lip section. Nozzle D is similar to nozzle C, with the chevrons tilted in an angle with respect to the nozzle axis on the plane of the nozzle wall. All the nozzles have a penetration angle of 10 degrees into the jet issuing from the nozzles. Comparative analysis of shock structures in jet from the different nozzles has been done and results are provided. [ABSTRACT FROM AUTHOR]

The sensitivity of the ceramic sheet sealed single-handle dual-control nozzle is an important indicator to verify its eligibility. This paper introduces the mechanical structure design of a faucet sensitivity detection device based on a microcontroller. The mechanical structure of the whole set of equipment is designed by three modules: electric control device, test bench main body and constant temperature water tank. The mechanical design is carried out with SolidWorks software. The control system uses the low-power STM32F4 chip as the main control chip. Through the control of the stepper motor, the water pump and the cylinder, the sensor data of temperature, pressure and flow is collected, and the data is displayed on the industrial PC to realize the test. Features. Experiments show that the device can quickly and stably perform the nozzle sensitivity test. [ABSTRACT FROM AUTHOR]

GESITS is an Indonesia electric scooter with design and manufacture in Institute of Technology Sepuluh Nopember (ITS) Surabaya, Indonesia. It is the first electric scooter in Indonesia that developed by a group of Indonesian engineers and business people that banded together to deliver the product to the market. One of the key to the successful implementation of e-scooter is the water resistance performance test of the escooter. In order to accomplish the protection, it is important to conduct the water ingress test based on Standard IPX5. In this paper explains the water resistance performance test for GESITS and then discuss some results. In accordance with the test procedure to evaluate IPX5 protection against ingress of water, the water resistance shall be carried out by spraying with a stream of fresh water the enclosure from all practicable directions with a standard test nozzle. The results showed that after finished the test and analyzing both the battery compartment and the controller compartment, it was determined that GESITS passes Ingress Protection and meets the engineering requirements. No water was observed inside the compartment during the visual inspection performed after the IPX5 exposure. Thus the degree of protection against water corresponds to IPX5 for GESITS. A visual inspection conducted upon completion of the exposure period also found no visible evidence of damage or degradation. It can be concluded that the result comply with the requirements since there wasn't any water that entered the enclosure. [ABSTRACT FROM AUTHOR]