Influence Of Inlet Parameters Research Articles

Comprehensive dynamic numerical simulation of cooling process for a 1.3GHz 9-cell superconducting cavity based on different structures

As an indispensable component of X-ray free electron lasers and future ring electron-positron colliders, a 1.3 GHz 9-cell superconducting cavity provides higher acceleration voltage and higher RF power per unit length, and saves equipment space. During testing and operation, superconducting cavities often need to be cooled gradually from the ambient temperature (300 K) to the superconducting temperature (4.5 K or less). To avoid plastic deformation of materials and seal leaking caused by high thermal stress, the cooling rates in each stage and the temperature differences on the cavity must be properly controlled. Currently, a less effective manual control strategy is typically used, whose main limitations include a low level of automation, a high reliance on the experience of the operating personnel, and a fairly lengthy time due to low efficiency. In this paper, a 1.3 GHz 9-cell superconducting cavity and its helium vessel were taken as the research subjects, six different mechanical structures of the helium vessel were designed, and six different three-dimensional thermal-flow coupling models were established. For each structural model, the temperature distribution and cooling strategy were analyzed using fluid numerical simulation software. The influence of inlet parameters on the cooling process was analyzed, and the appropriate mechanical structure model was recommended. The results showed that: During the cooling process, the closer the superconducting cavity is to the inlet, the lower the temperature is. The cooling rate is faster in the early stage in which the temperature difference can be reduced by 50 % within the first 30 min. After experimental test verification, the total cooling time is about 650 min (10.8 h or so), and the deviation between the simulation results and the experimental test results is less than 7 %, which shows the simulation results can well predict the actual cooling process for 1.3 GHz 9-cell superconducting cavity. The research work in this paper can lay a good foundation for the further R&D status of the superconducting cavity.

Influence of Inlet Parameters on Power Characteristics of Bernoulli Gripping Devices for Industrial Robots

There is a wide variety of gripping devices with various parameters at the present stage of development of robotics. However, the existing literature about the power characteristics of pneumatic gripping devices does not provide any analysis of the different types of input parameters other than supply pressure and flow characteristics, whereas the input parameters completely determine the technical characteristics of the gripping devices of industrial robots. In particular, for pneumatic grippers, the input parameters play a crucial role in their productivity and energy efficiency. This paper fills the gap by providing a study of the impact of such parameters on the power and energy characteristics of Bernoulli ejection grippers for industrial robots, including: the parameters of the compressed air inlet design, the parameters of the fitting for compressed air supply, the diameter of the hose for compressed air supply, and the size of the vacuum zone. First, this paper presents the results of theoretical studies and finite element method for determining the distribution of pressure on the surface of an object of manipulation, which allows one to determine the lifting force of the Bernoulli gripping devices of an industrial robot. It is determined that the horizontal air flow to the capture chamber, compared with that of the vertical, should be used to ensure the maximum possible lifting force. Structures and constriction in fittings, which are used to supply compressed air to the chamber of Bernoulli gripping devices, are considered. Then, the dependencies of the influence of narrowing the fittings on the power characteristics of gripping devices are presented.

Influence assessment of inlet parameters on thermal risk and productivity: Application to the epoxidation of vegetable oils

The influence of inlet parameters on the production and thermal risk of complex chemical systems can be cumbersome to evaluate. To determine the optimum safe operating conditions, one needs to solve complex differential equations derived from energy and material balances. This robust approach cannot be made on-site, and it is essential to propose simplest tools to evaluate rapidly the performance and safety of some operating conditions. This is the aim of this paper that establishes explicit relationships between the production and thermal risk parameters, and the inlet parameters. In addition, it also proposes a Pareto chart that can be used to make the tradeoff between safety and performance. Such relationships and chart were developed for the production of epoxidized cottonseed oil under isoperibolic and semi-batch mode. The kinetic model developed by Zheng et (Zheng et al., 2016). was used. First, a numerical approach, i.e., least square method, was used to find explicit relationships between thermal risk parameters, production parameters and six inlet parameters. The use of such an approach allows a better understanding of this process. Second, safety and performance indicators are proposed and discussed to evaluate the operating conditions thanks to a simple and intuitive schema. Besides, this approach can be used to find the optimum conditions more rapidly.

Modeling and performance investigation on the counter-flow ultrasonic atomization liquid desiccant regenerator

As the key components in a liquid desiccant dehumidification system, liquid desiccant regenerator produces great effect on the whole system’s performance. This paper studies the counter-flow ultrasonic atomization liquid desiccant regenerator. Firstly, a mathematical model for the regenerator has been established and experimentally validated with finite difference method. Two performance indicators, i.e., the moisture removal rate and the regeneration thermal efficiency, were suggested to evaluate the performance of the counter-flow regenerator, and the influences of inlet parameters on the regeneration performance of the counter-flow regenerator have been investigated by the established model in this study. Decreasing temperature difference and increasing humidity difference between air and solution can improve regeneration performance. With the temperature of air and solution increasing, the regeneration efficiency increases, but the energy loss also increases. The regeneration efficiency decreases with the increase of solution concentration. The regeneration efficiency increases nonlinearly with the increase of gas-liquid ratio. Finally, there exists an optimum droplet size for the best regeneration performance. Compared with the parallel-flow configuration, the counter-flow has better regeneration performance, which is attributed to the more uniform distribution of moisture transfer driving force and the longer residence time of droplets in the regenerator. The study contributes to the development and the better applications of the counter-flow ultrasonic atomization liquid desiccant regenerator.

Experimental investigation of the regeneration performance of an internally heated regenerator used for heating tower solution regeneration

Abstract Owing to their high cooling efficiency in summer and frost-free characteristics in winter, heating tower heat pumps are becoming increasingly popular. However, the solution will be diluted during heating due to absorbing moisture from the air, and should be properly regenerated for continuous operation. In this study, a novel heat recovery solution regeneration system using an internally heated regenerator is proposed for antifreeze solution regeneration. A test bench is fabricated to investigate the regeneration performance of the internally heated regenerator. Correlations of the heat and mass transfer coefficients are proposed, and agree well with the experimental data. The influences of inlet parameters on the moisture removal rate, latent heat ratio, and humidity effectiveness are evaluated and compared to those for internally heated liquid desiccant regeneration. The results indicate that: the regeneration performance of the internally heated regenerator is affected mainly by the air flow rate, heating water flow rate, and inlet temperature of heating water. The moisture removal rate increases remarkably with increasing the heating water flow rate and inlet temperature of heating water. The latent heat ratio decreases significantly with increasing the inlet temperature of heating water. The humidity effectiveness decreases remarkably with increasing the air flow rate. The influences of the above inlet parameters on performance indices in the present study exhibit the same trends as those reported for internally heated liquid desiccant regeneration. However, compared with internally heated liquid desiccant regeneration, the regeneration temperature for internally heated antifreeze solution regeneration is much lower. This suggests that a low-grade heat source can be used to meet the antifreeze solution regeneration demands.