Influence of contraction of a cesium pulse-periodic discharge on its luminous efficacy and spectral properties

The paper presents the results of a study of pulse-periodic discharge cesium lighting lamps with discharge tubes 5 mm in diameter and an interelectrode distance of 55 and 22 mm. The cesium pressure varied from 10 to 750 Torr at a constant triangular current pulse with an amplitude of 80 A. It is shown that the maximum of the luminous efficacy (~ 65 lm/W) corresponds to a pressure of ~ 130 Torr. It was found that a discharge column in the long tube at a pressure of ~ 300 Torr contracted into a bright pinch with a diameter close to that of the electrodes (2 mm). The pinch was localized along the surface of the tube and moves randomly on it. Contraction leads to a repeated increase in the luminous efficacy with pressure up to ~ 70 lm/W. Wall stabilization limits the plasma temperature on the axis of the pinch (it was found from the recombination continuum) to the level of 6000 – 6500 K. The column in short tube is localized along the axis of the tube over the entire power range. The temperature in it quickly rises to 13000-– 14000 K after the maximum of the luminous efficacy.

Performance Scrutiny of Domestic Refrigerator Using a Stepped Mini Orifice as A Capillary Tube Extension with Sio2 Nano Lubricant And R-290 Refrigerant

A stepped short tube orifice has been proposed as a replacement for the expansion mechanism in a residential refrigerator that runs on R-290. The present work is primarily concerned with the impacts of stepped short tube orifices on system characteristics such as net refrigeration effect, compressor effort, pull down time, and coefficient of performance. A stepped short tube orifice is made up of two short tube orifices linked serially and having varying sizes. It is used as an extension to the capillary tube in the refrigeration system. A stepped short tube orifice is built and fitted to a home refrigerator in this experiment. The experiments must be done on a home refrigerator equipped with a stepped short tube orifice, R-290 refrigerant, and a 0.5% weight SiO2 nanoparticle. Following the completion of all trials, the effects of the stepwise short tube orifice on a residential refrigerator were studied using comparison charts. The results indicate that the performance of the home refrigerator with stepped short tube orifice and SiO2 nano particle inclusion was much better than the domestic refrigerator without stepped short tube orifice.

Pipes Construction Based on the Pipes' Centre Curve Shapes

Parts of pipeline need a long piece, a short segment, and various inflate-deflate models. They require as well the thickness and curvature of the pipes. The objective of this paper is to obtain some formulas for modeling the long pipe, the short tube, and various inflate-deflate pipe patches. Relating to the purposes, we use their cross-section, longitudinal section, and center curves of the pipe parts. The methods are, the using of the polar coordinates and of the real functions, to define the cross and longitudinal section of the pipe patches, respectively. Then, we calculate three orthonormal vectors that are determined by the tangent vectors of the pipe center curves and two unit vectors that are perpendicular to the tangent vectors. After that, we evaluate the formulas to model the long pipes and the short pipes, both inflate-deflate and thickness shapes. The results show that, using its center curves of the pipe, it is handy to design the long and short pipes, multiple thicknesses, various volume fluctuations of the pipes, and useful to model the inflate-deflate pipe parts.

A new method for calculating the sonic conductance of airflow through a short-tube orifice

In this study, we proposed a method for calculating the sonic conductance of a short-tube orifice. First, we derived a formula for calculating the sonic conductance based on a continuity equation, a momentum equation and the definition of flow-rate characteristics. The flow-rate characteristics of different orifices were then measured using the upstream constant-pressure test method in ISO 6358. Based on these test data, the theoretical formula was simplified using the least squares fitting method, the accuracy of which was verified experimentally. Finally, the effects of the diameter ratio, the length-to-diameter ratio and the critical pressure ratio were analysed with reference to engineering applications, and a simplified formula was derived. We conclude that the influence of the diameter ratio is greater than that of the length-to-diameter ratio. When the length-to-diameter ratio is <5, its effect can be neglected. The critical pressure ratio has little effect on the sonic conductance of a short-tube orifice, and it can be set to 0.5 when calculating the sonic conductance in engineering applications. The formula proposed in this study is highly accurate with a mean error of <3%.