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  • 101.
    Wang, Wujun
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Xu, Haoxin
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Strand, Torsten
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Conjugate heat transfer analysis of an impinging receiver design for a dish-Brayton system2015In: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 119, p. 298-309Article in journal (Refereed)
    Abstract [en]

    An impinging receiver design has been developed for a small scale solar dish-Brayton system. A numerical conjugate heat transfer model combined with a ray-tracing model, based on the boundary conditions of the micro gas turbine and the EuroDish system, has been used for studying the thermal performance of an impinging receiver. According to the results of the preliminary estimation by an inverse design method, four possible impinging nozzle arrangements have been studied by the numerical model based on a 240 mm diameter and 3 mm wall thickness cavity. The inverse design method has been verified to be an efficient way in reducing the calculation costs during the design procedure. Furthermore, the impacts of the cavity diameter and the wall thickness have also been studied.

  • 102.
    Wang, Wujun
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Malmquist, Anders
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Aichmayer, Lukas
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Transient performance of an impinging receiver: An indoor experimental study2018In: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 158, p. 193-200Article in journal (Refereed)
    Abstract [en]

    The impinging receiver is a new member of the cavity solar receiver family. In this paper, the transient performance of a prototype impinging receiver has been studied with the help of a Fresnel lens based solar simulator and an externally fired micro gas turbine. The impinging receiver can offer an air outlet temperature of 810 °C at an absorber temperature of 960 °C. The radiative-to-thermal efficiency is measured to be 74.1%. The absorber temperature uniformity is good but high temperature differences have been detected during the ‘cold startup’ process. The temperature changing rate of the receiver is within 3 °C/s for the startup process and 4 °C/s for the shut-down process. In order to avoid quenching effects caused by the impinging jets, the micro gas turbine should be turned off to stop the airflow when the radiative power is off. 

  • 103.
    Wang, Wujun
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Malmquist, Anders
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Comparison of potential control strategies for an impinging receiver based dish-Brayton system when the solar irradiation exceeds its design value2018In: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 169, p. 1-12Article in journal (Refereed)
    Abstract [en]

    Potential control strategies for an impinging receiver based dish-Brayton system have been presented for protecting the key components from the risks of overheating when the solar irradiation exceeds its design value. Two of them are selected for a detailed study: changing the effective diameter of the shading device and changing the inlet temperature. A rope-pulley shading device is developed for controlling the shading area in the center of the dish, and the change of the inlet temperature is achieved by applying a bypass at the cold side of the recuperator for reducing the heat transfer rate. Both control strategies can manage the peak temperature on the absorber surface within 1030 °C with an outlet temperature fluctuation between −4.1 and 15.1 °C, so that the impinging receiver can work for long time at any solar direct normal irradiance value. Furthermore, the temperature differences on the absorber surface are between 137.1 °C and 163.8 °C. The cases that are achieved by changing the shield effective diameter are significantly lower (11–26 °C) than the corresponding cases that are achieved by changing the inlet temperature.

  • 104.
    Wang, Wujun
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Ragnolo, Gianmarco
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Aichmayer, Lukas
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Strand, Torsten
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Integrated Design of a Hybrid Gas Turbine-Receiver Unit for a Solar Dish System2014In: Proceedings of the International SolarPACES Conference 2014. Beijing, China. September 16-19, 2014, 2014Conference paper (Refereed)
    Abstract [en]

    An integrated design concept of a 25 KWel hybrid gas turbine-receiver unit is introduced in this paper. In this design, hot section; receiver, combustor and turbine, is integrated and located in the center of the unit in order to achieve a compact structure with low heat loss and cooling requirement. A ray tracing model is developed for analyzing the focal plane of the potential parabolic dish design and predicting the radiative flux boundary conditions of the receiver. An impinging cavity receiver, with a cylindrical absorber wall and a semi-spherical bottom, is chosen as the receiver for this hybrid unit. The cooling capacities of different impinging arrangements are calculated to determine the thermal boundary conditions on the cooling side. Finally, the optimal dimensions of the receiver are chosen as well as the impingement cooling design. A ‘single ring’ impinging array was found to be optimal for cooling down the wall temperature of the peak flux region to 1200 °C and provide a receiver exit temperature of 840 °C.

  • 105.
    Wang, Wujun
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Wang, Bo
    Li, Lifeng
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Strand, Torsten
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    The effect of the cooling nozzle arrangement to the thermal performance of a solar impinging receiver2016In: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 131, p. 222-234Article in journal (Refereed)
    Abstract [en]

    The effect of the multi-row nozzle arrangement to the thermal performance of an impinging solar receiver is studied, and new governingequations are introduced for modifying the earlier introduced inverse design method. With the help of the modified inverse designmethod and a numerical conjugate heat transfer model, an impinging receiver based on stainless steel 253 MA material has been designedfor the combination of a micro gas turbine and the EuroDish collector system. At a DNI level of 800 W/m2, the average air temperatureat the outlet and the thermal efficiency can reach 1071.5 K and 82.7%. Furthermore, the temperature differences on the absorber can bereduced to 130 K and 149 K for two different DNI levels respectively. This represents a greatly improvement compared with other publishedcavity receiver designs.

  • 106.
    Wang, Wujun
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Xu, Haoxin
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Strand, Torsten
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    An inverse design method for a cavity receiver used in solar dish Brayton system2014In: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 110, p. 745-755Article in journal (Refereed)
    Abstract [en]

    An inverse design method is developed in order to quickly find possible cavity receiver designs with relative uniform cavity wall surface temperature for a solar dish cavity receiver. In this design method, a heat transfer model of the absorber wall is used for analyzing the main heat transfer process between the cavity wall outer surface, the inner surface and the working fluid. Furthermore, a ray-tracing model based on the parameters of a real dish is utilized for obtaining the solar radiative boundary conditions for the heat transfer model. Impinging jet cooling technology is introduced due to its high heat transfer coefficient in the stagnation area, which can be used for cooling the peak flux on the cavity wall. After applying a well-designed impinging system, the temperature peak on the peak flux region in traditional receiver designs can be mitigated without introducing any over pressure drop problem.

  • 107.
    Winterfeldt, Lars
    et al.
    Volvo Aero.
    Laumert, Björn
    Volvo Aero.
    Tano, Robert
    Volvo Aero.
    James, P.
    Snecma Safran.
    Geneau, F.
    Snecma Safran.
    Hagemann, G.
    EADS Space Transportation.
    Redesign of the Vulcain 2 Nozzle Extension2005In: 41st AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, 2005Conference paper (Refereed)
    Abstract [en]

    The Vulcain 2 Nozzle Extension has been reinforced further to the failure of the maiden flight of Ariane 5 ECA. An intensive engineering and testing program was pursued by Volvo Aero Corporation (VAC), responsible for the Nozzle Extension, EADS-ST GmbH responsible for the Thrust Chamber and Snecma, responsible for the Vulcain 2 engine. This program was conducted under the leadership of CNES, by delegation of ESA. Thanks to the use of advanced computational methodologies and an integrated engineering team from Volvo Aero Corporation, EADS-ST GmbH and Snecma, the nozzle modifications defined at the early stage of the development fulfilled completely their requirements. Extreme ground tests have been defined to reproduce the worst loads expected in flight and have demonstrated the robustness of the Vulcain 2 Nozzle Extension.

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