Nonlinear Dynamics  Modelling of a Pendulum Rotor using Trigonometry Analysis  

WXianghe Dai

 Abstract

In this paper, the nonlinear dynamics of a pendulum rotor was analyzed using numerically and analytically methods. A mathematical model was firstly defined to examine the forced chaotic dynamical behavior of a pendulum rotor with considering the rub interaction between a rotor and a boundary with a non-linear restoring force. A second order ODE's were resulted from the mathematical model where the design variables can be reduced through using a non-dimensional group of variables. Particular concentration is given to evaluate the impacts of friction coefficient, clearance, and structural damping on the nonlinear behavior (chaotic behavior). This response of the nonlinear system was estimated through using numerical analyses software’s such as using Matlab. By these analyses, the differences between the nonlinear response and the usual linear assumptions can be evaluated. Within the project, the work will complement some current research in the dynamics lab, and there is potential to incorporate some experimental work

Concentrated Solar Plant with Bio-Gas as an Alternative to Natural Gas 

Andrew, C  Yan, C  Lew, Y

 Abstract

 This study discusses briefly the essential role provided by a thermal solar plant to an existing power station. This type of solar panels effected positively in achieving higher rates of decarbonisation. Among all available CSP types in the global market, the parabolic trough collectors considered being the most common used panels. Manufacturer and suppliers provide about 85% of the CSP industrial capacity to the parabolic trough type. The provided study depended on viewing the main performance provided by cooperating a commercial concentrated solar plant to a conventional power station. A concentrated power plant located in the Ciudad Real region was under investigation, the system is a wet-cooled CSP (parabolic trough technology) that generates 50 MWe. The heat transfer fluid in this system was synthetic oil incorporates a 7.5h molten salt, it is a two tanks configuration 

Lawis Samson  

 Abstract

 The studied system used the molten salt as a heat transfer fluid, the fluid choice based upon the massive ability of storing heat energy comparing with synthetic oil. Steam is heated up to 543 oC by the molten salt. As viewed in fig.1, scheme I represents the modified boiler. SPT solar energy is used to superheat steam in the coal power plant. The inlet of LSH is selected as a place to extract a predetermined amount of steam, which transported to the molten salt heat exchanger. The previously discussed selection procedure of the LSH comes as a result of the high complexity and instability of cladding super-heater. After heat is delivered to the molten salt heat exchanger, a deeper reheating is accomplished relying upon feeding heated heat transfer fluid (molten salt) to the final super heater. The final step is achieved by allowing steam exists in the final super heater to be heated again using fossil fuels such as coal or natural gas until reaching the rated operating condition. Only the superheat part of the boiler is integrated with heated molten salt. Actually, the heaviest thermal load in the boiler is in the evaporating part as it is required to add both necessary sensible and latent heat. Scheme II illustrated in the figure as well, the point of extraction turns into the economizer’s outlet. The molten salt is then located before the final super heater. Unlike to Scheme I, extracted medium in Scheme II differs compared with steam to the subcooled water consequently, the molten salt should include the evaporating and superheating parts. Operating temperature range changed reaching to (310 to 540 oC) that defines the average endothermic operating temperature of the combined cycle is decreased. For achieving higher level of safety to the boiler, an attemperation is utilized to it ahead of both the heat exchangers. The attemperation main function is to prevent any possibility of increasing steam temperature at the outlet of PSH and FSH above the designed temperature; they could be noticed in the figure below AW1 and AW2. Exceeding operating temperature would result in thermal stresses and micro cracks appearance consequently, lower service time and economic loss. A temperature range confirmation should be known in the double system boiler. Maximum temperature deviation is ½ oC, which means a higher accuracy and precision obtained during the discussed study. The designed thermal storage system operating with molten salt as a heat transfer fluid exists in the integration system, its main function is to adjust all the system’s fluctuations as a result of sunlight well and increasing both the safety and stability levels of the complementation  

 San , W  Miguel , A

 Abstract

 The research intended to choose the most suitable type of solar collector among possible types discussed before. An optimum type selection should consider all operating parameters such as the efficiency, reliability, flexibility, maintenance, service time, availability in the global market, and the economic benefits. Researchers provided many studies to compare each type’s performance to reach weak and strong utilization points. The standard ISO 9809 is used to measure the solar collectors’ performance, which describe briefly the plant’s behaviour during its operation. In fact, manufacturers could not provide engineers by a final reading such as the power that indicates the overall output (as PV panels). An evacuated tube arrays installed on a building’s roof typically contains open volumes between the solar collector tubes. In addition, vacuum space located between both the concentric tubes (made of glass or metal) of each collector. The designed tubes installed to cover an available space on a roof. A comparison between evacuated tubes and flat-plate collectors based on area of roof occupied would differs much than the comparison between them based on the absorbing area (heat transfer surface area), an essential conclusion might be understood. Flat plate collectors usually cause higher heat loss to the environment if compared with the evacuated tubes due to the increasing of operating temperature. Evacuated tubes are not suitable for high temperature engineering applications such as utilizing them for steam production in power stations. Evacuated tube collectors estimated to gain less heat transfer area, gross area ratio (typically 60–80% of gross area) if compared with flat plates’ heat transfer area (absorbing area). On the other hand, almost all evacuated tube systems consider providing more efficient performance per each square meter if compared with the same heat transfer area in case of the flat plate solar collectors consequently, evacuated tubes solar collectors are more suitable in case of roof space is limiting