A Mass Computation Model for Light Weight Brayton Cycle Regenerator Heat Exchangers

Juhasz, Albert J.

doi:10.2514/6.2010-7087

Cited by 8 publications

(6 citation statements)

References 5 publications

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“…A 65 ppi, 25% dense foam has a higher specific area (∼6000 m 2 /m 3 compared to ∼3000 m 2 /m 3 ) than the best flat-plate heat exchangers and can operate at higher temperatures than most flat-plate joining allows [15]. They are also easier and less expensive to fabricate.…”

Section: Refractory Heat Exchangersmentioning

confidence: 94%

Design and fabrication of a high-temperature helium regenerator

Youchison

Garde

2012

Fusion Engineering and Design

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a b s t r a c tRefractory metallic foams can increase heat transfer efficiency in gas-to-gas and liquid metal-to-gas heat exchangers by providing an extended surface area for better convection, i.e. conduction into the foam ligaments providing a "fin-effect," and by disruption of the thermal boundary layer near the hot wall and ligaments by turbulence promotion. In this article, we describe the design of a high-temperature refractory regenerator (closed-loop recuperator) using computational fluid dynamics (CFD) modeling of actual foam geometries obtained through computerized micro-tomography. The article outlines the design procedure from geometry import through meshing and thermo-mechanical analysis and discusses the challenges of fabrication using pure molybdenum and TZM. The foam core regenerator is more easily fabricated, less expensive and performs better than refractory flat plate-type heat exchangers. The regenerator can operate with a maximum hot leg inlet temperature of 900 • C and transfer 180 kW to the cold leg using 100 g/s helium at 4 MPa. Future high heat flux experiments on helium-cooled plasma facing components will utilize the high temperature and high pressure capabilities of this unique regenerator. Similar components will be required to adapt fusion power reactors to high-efficiency Brayton power conversion systems and enable operation of advanced divertor and blanket systems.

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Section: Refractory Heat Exchangersmentioning

confidence: 94%

Design and fabrication of a high-temperature helium regenerator

Youchison

Garde

2012

Fusion Engineering and Design

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“…Power output for a given material mass was calculated, adding the thermoelectric material, the cold plate with water passage, and another plate with gas passage. The cost for the heat transfer section draws upon data for the mass per thermal resistance for both the hot-and cold-side plates [28]. Figure 13 shows the cost as a function of the flow rate of the working fluid.…”

Section: Cost Analysismentioning

confidence: 99%

Heat Flux Based Optimization of Combined Heat and Power Thermoelectric Heat Exchanger

Yazawa

Shakouri

2021

Energies

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We analyzed the potential of thermoelectrics for electricity generation in a combined heat and power (CHP) waste heat recovery system. The state-of-the-art organic Rankine cycle CHP system provides hot water and space heating while electricity is also generated with an efficiency of up to 12% at the MW scale. Thermoelectrics, in contrast, will serve smaller and distributed systems. Considering the limited heat flux from the waste heat source, we investigated a counterflow heat exchanger with an integrated thermoelectric module for maximum power, high efficiency, or low cost. Irreversible thermal resistances connected to the thermoelectric legs determine the energy conversion performance. The exit temperatures of fluids through the heat exchanger are important for the system efficiency to match the applications. Based on the analytic model for the thermoelectric integrated subsystem, the design for maximum power output with a given heat flux requires thermoelectric legs 40–70% longer than the case of fixed temperature reservoir boundary conditions. With existing thermoelectric materials, 300–400 W/m2 electrical energy can be generated at a material cost of $3–4 per watt. The prospects of improvements in thermoelectric materials were also studied. While the combined system efficiency is nearly 100%, the balance between the hot and cold flow rates needs to be adjusted for the heat recovery applications.

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“…Basic sizing data is needed for the heat exchanger for modelling its transient operation and for evaluating its weight, namely the characteristic length, area, volume and mass. These values are calculated according to the simplified method described by Juhasz [42] and adopting the values suggested by the author, specifically: heat transfer coefficient equal to 142 W/(m 2 K), density equal to 3900kg/m 3 and packing density of 3281m 2 /m 3 . The heat exchanger pressure drop at design point is assumed 4% for the cold side and 5% for the hot side including the exit duct losses, in line with the values suggested in [20].…”

Section: Recuperated Enginementioning

confidence: 99%

Assessment of Thermo-Electric Power Plants for Rotorcraft Application

Roumeliotis

Mourouzidis

Zafferetti

et al. 2020

Journal of Engineering for Gas Turbines and Power

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This paper assesses a parallel electric hybrid propulsion system utilizing simple and recuperated cycle gas turbine configurations. An adapted engine model capable to reproduce a turboshaft engine steady state and transient operation is built in Simcenter Amesim and used as a baseline for a recuperated engine. The transient operation of the recuperated engine is assessed for different values of heat exchanger effectiveness, quantifying the engine lag and the surge margin reduction which are results of the heat exchanger addition. An oil and gas (OAG) mission of a twin engine medium helicopter has been used for assessing the parallel hybrid configuration. The thermoelectric system brings a certain level of flexibility allowing for better engine utilization, thus first a hybrid configuration based on simple cycle gas turbine scaled down from the baseline engine is assessed in terms of performance and weight. Following the recuperated engine, thermoelectric power plant is assessed and the performance enhancement is compared against the simple cycle conventional and hybrid configurations. The results indicate that a recuperated gas turbine based thermo-electric power plant may provide significant fuel economy despite the increased weight. At the same time, the electric power train can be used to compensate for the reduced specific power and potentially for the throttle response change due to the heat exchanger addition.

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A Mass Computation Model for Light Weight Brayton Cycle Regenerator Heat Exchangers

Cited by 8 publications

References 5 publications

Design and fabrication of a high-temperature helium regenerator

Design and fabrication of a high-temperature helium regenerator

Heat Flux Based Optimization of Combined Heat and Power Thermoelectric Heat Exchanger

Assessment of Thermo-Electric Power Plants for Rotorcraft Application

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