injection coefficient
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2021 ◽  
Vol 2131 (2) ◽  
pp. 022059
Author(s):  
K K Kim

Abstract When creating MHD (Magnetohydrodynamic) alternating current generators using liquid-metal working body, the latter is accelerated by piston method, in which the working body is a periodic structure of alternating zones of liquid metal (pistons) and zones of compressed gas, the latter is accelerated liquid-metal pistons. This raises the form stability problem for liquid metal pistons. Viscous frictional forces generated inside the pistons lead to the destruction of the pistons and significantly reduce the efficiency of the MHD unit. One solution is to use gas-permeable walls of the channels of MHD-generators, through the pores of which gas is injected. In this way, the piston flow is isolated from the side surface of the channel by the penetrating gas in the channel cavity. As a result, friction losses are drastically reduced. At the final values of the One solution is to use gas-permeable walls of the channels of MHD-generators, through the pores of which gas is injection coefficients, (? ≥ 0.03)the friction practically disappears. With the channel length determined by the coordinate of the maximum piston speed, 92% of the current marginal efficiency values can be achieved. The maximum efficiency of the runaway channel can be achieved by selecting the optimal value of the air injection coefficient. The operation of the devices commutating the injected gas must ensure that there is an injection in an area that is no more than twice the length of the piston.


2021 ◽  
Vol 2094 (2) ◽  
pp. 022032
Author(s):  
N V Medved ◽  
E L Egorova ◽  
V N Morozov ◽  
V A Gron ◽  
A V Galaiko

Abstract The article presents the results of the dredger in a deep deposit of sand and gravel materials. It was found that when the diameter of the suction pipe exceeds the diameter of the inlet mixing chamber by 150 mm, the actual pressure from the ejector does not exceed one meter, and with an increase in the supply of the suction pump as a result of a sharp jump in hydraulic resistance, the vacuum is disrupted. It was also found that the effect on the calculated compression ratio of the jet apparatus increases with an increase in the injection coefficient and the input velocity of the injected stream.


2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Binglong Zhang ◽  
He Liu ◽  
Jianhua Zhou ◽  
Hui Liu

AbstractThe forward variable area bypass injector (FVABI) is a key component of double bypass variable cycle engine (VCE) to achieve mode transition and bypass ratio adjustment. In this paper, an experimental system for FVABI was constructed based on the analysis of relevant experimental theories, and then the experiments on FVABI were carried out for a specific working state in double bypass mode of VCE and for the comparison working states with different area ratios and different back pressure ratios. The results showed that the FVABI designed in this paper meets the requirements of VCE at this working state. The analysis of the influence of area ratio and back pressure ratio on the injection coefficient showed that the first bypass valve and back pressure were effective means to control the mass flow of FVABI.


2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Binglong Zhang ◽  
He Liu ◽  
Jianhua Zhou ◽  
Hui Liu

Abstract The forward variable area bypass injector (FVABI) is a key component of double bypass variable cycle engine (VCE) to achieve mode transition and bypass ratio adjustment. In this paper, an experimental system for FVABI was constructed based on the analysis of relevant experimental theories, and then the experiments on FVABI were carried out for a specific working state in double bypass mode of VCE and for the comparison working states with different area ratios and different back pressure ratios. The results showed that the FVABI designed in this paper meets the requirements of VCE at this working state. The analysis of the influence of area ratio and back pressure ratio on the injection coefficient showed that the first bypass valve and back pressure were effective means to control the mass flow of FVABI.


2020 ◽  
Vol 157 ◽  
pp. 06037
Author(s):  
Dmitry Kitaev ◽  
Egor Aralov ◽  
Dmitry Bugaevsky ◽  
Artem Makarov

One of the energy-efficient technologies is the use of injectors in heat supply systems. Steam-water injectors are very sensitive to changes in the thermodynamic parameters of water and steam. The operating range of such devices is limited to boiling liquids. The search for ranges of thermodynamic parameters that ensure the operation of the injector in real conditions of functioning of heating networks is an urgent task. The maximum energy-saving effect can be achieved by replacing devices that reduce steam pressure by injectors in which there will be a simultaneous decrease in steam pressure, heat transfer between steam and return network water to achieve the necessary thermodynamic parameters of the mixed flow. The article presents the results of modeling the operation of a steam-water injector with a cylindrical mixing chamber, taking into account the actual values of temperatures and pressures in the heating network. With constant parameters of hot steam, the possible ranges of the injector for the temperatures and pressures necessary for the implementation of temperature schedules for regulating heating networks are determined. The procedure for identifying input parameters that ensure the implementation of temperature schedules of heating networks has been carried out. Equations are obtained that allow one to determine the temperature of the water leaving the injector from the injection coefficient for the found working pressure ranges of the injected water.


Electronics ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 685
Author(s):  
Jiao Jiao ◽  
Lingda Wu ◽  
Kechang Qian

In order to improve the spatial resolution of multispectral (MS) images and reduce spectral distortion, a segmentation-cooperated pansharpening method using local adaptive spectral modulation (LASM) is proposed in this paper. By using the k-means algorithm for the segmentation of MS images, different connected component groups can be obtained according to their spectral characteristics. For spectral information modulation of fusion images, the LASM coefficients are constructed based on details extracted from images and local spectral relationships among MS bands. Moreover, we introduce a cooperative theory for the pansharpening process. The local injection coefficient matrix and LASM coefficient matrix are estimated based on the connected component groups to optimize the fusion result, and the parameters of the segmentation algorithm are adjusted according to the feedback from the pansharpening result. In the experimental part, degraded and real data sets from GeoEye-1 and QuickBird satellites are used to assess the performance of our proposed method. Experimental results demonstrate the validity and effectiveness of our method. Generally, the method is superior to several classic and state-of-the-art pansharpening methods in both subjective visual effect and objective evaluation indices, achieving a balance between the injection of spatial details and maintenance of spectral information, while effectively reducing the spectral distortion of the fusion image.


Photonics ◽  
2019 ◽  
Vol 6 (2) ◽  
pp. 58 ◽  
Author(s):  
Zai-Fu Jiang ◽  
Zheng-Mao Wu ◽  
Elumalai Jayaprasath ◽  
Wen-Yan Yang ◽  
Chun-Xia Hu ◽  
...  

We numerically investigate the nonlinear dynamic properties of an exclusive excited-state (ES) emission quantum dot (QD) laser under optical injection. The results show that, under suitable injection parameters, the ES-QD laser can exhibit rich nonlinear dynamical behaviors, such as injection locking (IL), period one (P1), period two (P2), multi-period (MP), and chaotic pulsation (CP). Through mapping these dynamic states in the parameter space of the frequency detuning and the injection coefficient, it can be found that the IL occupies a wide region and the dynamic evolution routes appear in multiple forms. Via permutation entropy (PE) calculation to quantify the complexity of the CP state, the parameter range for acquiring the chaos with high complexity can be determined. Moreover, the influence of the linewidth enhancement factor (LEF) on the dynamical state of the ES-QD laser is analyzed. With the increase of the LEF value, the chaotic area shrinks (expands) in the negative (positive) frequency detuning region, and the IL region gradually shifts towards the negative frequency detuning.


2018 ◽  
Vol 12 (5) ◽  
pp. 31-38
Author(s):  
L. A. Marchenko ◽  
M. A. Safonov

Agricultural boom sprayers are equipped with injection sprayers of mainly foreign origin. The main parameters of the injection sprayers shown in the catalogs display the consumption characteristics in cer­tain ranges without taking into account the design parameters.(Research purpose)Determination of the design and technological parameters of an injection sprayer for the introduction of pesticides.(Materials and methods)The injection sprayer belongs to the class of two­phase liquid­gas isothermal jet devices with the formation of an air­gas mixture at the outlet. It has been established that the design model of the working process of an injection sprayer is based both on the laws of the conservation of mass, energy, momentum, as well as theoretical relation­ships in the form of equations describing two­phase jet devices, and empirical relationships characterizing flow parameters, geometric transverse and longitudinal dimensions of the spray channels.(Results and discussion)The following analytical relationships have been obtained: the relative pressure difference generated by an injec­tion sprayer and the volume injection coefficient for different surface area ratios of the working nozzle to the flow section of the sprayer; the ratio between the cross­sectional area of the mixing chamber to the area of the working nozzle outlet and the injection ratio; relative pressure difference and the injection ratio; the ratio be­tween the cross­sectional area of the mixing chamber and the working nozzle and the relative pressure difference. The authors have determined a set of dimensionless pressure characteristics of the injection sprayer for different ratios between the cross­sectional areas of the working nozzle and the mixing chamber. It has been established that the ratio between the cross sections of the mixing chamber area and the working nozzle area increases as the injection ratio increases. It has been shown that for each injection coefficient, there is an achievable relative pressure difference in the injection sprayer.(Conclusions)The authors have proposed the design equations that determine the characteristics of an injection sprayer and its main design parameters – the diameters of nozzle and mixing chambers. They have calculated the main dimensions of the sprayer for aerial top­dressing by introducing working solutions of pesticides.


2014 ◽  
Vol 602-605 ◽  
pp. 680-683
Author(s):  
Zhen Ya Chen ◽  
Xing Quan Shen ◽  
Zhi Jie Xin

In the process of DF system machining the small diameter deep hole, the working parameters of negative pressure device has a great influence, including injection coefficient, chip removal of cross-sectional area ratio, discharge pressure, negative pressure number, etc. Injection coefficient has the non-linear proportional relationship with chip removal of cross-sectional area ratio, with the increasing incidence of negative pressure discharge pressure increases, as well as, increasing negative pressure number to improve chip removal have a good effect. Movement patterns of cutting fluid is simulated, energy loss of cutting fluid in the flow is studied, finding curved edge nozzle has better negative effects than straight edge nozzle. The effect of negative pressure pumping crumbs is analyzed, the injection process of negative pressure device is simulated, and the form of the fluid motion in negative pressure nozzle is got based on Fluent, which have a good guide for the actual production and machining.


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