Development of the Supercritical Carbon Dioxide Power Cycle Experimental Loop in KIER

Cho, Junhyun; Shin, Hyung-Ki; Ra, Ho-Sang; Lee, Gilbong; Roh, Chulwoo; Lee, Beomjoon; Baik, Young-Jin

doi:10.1115/gt2016-57460

Cited by 34 publications

(19 citation statements)

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“…The Korea Atomic Energy Research Institute has collaborated with the Korea Advanced Institute of Science [16,17]. KIER is currently developing a comprehensive test loop for the recuperated supercritical CO 2 Brayton cycle with a power output of tens to hundreds of kilowatt-electric.…”

Section: Introductionmentioning

confidence: 99%

Development of the turbomachinery for the supercritical carbon dioxide power cycle

Cho

Choi²,

Baik

et al. 2015

Int. J. Energy Res.

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SUMMARYA supercritical carbon dioxide power cycle has been focused as a promising power cycle because of its compactness, a high efficiency, and a wide applicability. A 10-kWe-class simple unrecuperated supercritical carbon dioxide Brayton experimental loop including a turbo-alternator-compressor unit using a centrifugal compressor and a radial turbine was developed. A shrouded type of a compressor impeller and a turbine wheel with labyrinth seals were designed to overcome thrust balancing problems of the high-pressure fluid turbomachinery. In addition, this type has no issues on the thermal growth collision failure and clearance loss between a shroud and a wheel. Preliminary operation at 30,000 rpm, turbine inlet temperature of 83°C, and pressure of 8500 kPa was successful. It is founded that all states of the cycle existed in the supercritical region.

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Section: Introductionmentioning

confidence: 99%

Development of the turbomachinery for the supercritical carbon dioxide power cycle

Cho

Choi²,

Baik

et al. 2015

Int. J. Energy Res.

Self Cite

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“…[76] (b) Photos of the gas foil bearings for use in the Gen IV turbomachinery, taken from Ref. [52] [83] (b) the basic sCO 2 cycle established by SNL [52], (c) the sCO 2 cycle established by KAIST [89] and (d) the KIER 10 kW test loop [90]. .…”

Section: 12mentioning

confidence: 99%

“…Figurefor experimental test rigs: (a) the 100 kW sCO 2 power cycle system test rig[83] (b) the basic sCO 2 cycle established by SNL[52], (c) the sCO 2 cycle established by KAIST[89] and (d) the KIER 10 kW test loop[90].…”

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confidence: 99%

Development and application of simulation tools for supercritical carbon dioxide radial inflow turbine

Qi¹

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Supercritical CO 2 (sCO 2) cycles are considered a promising technology for next generation concentrated solar thermal, waste heat recovery and nuclear applications. Particularly at small to medium scale, where radial inflow turbines can be employed, using sCO 2 results in both system advantages and simplifications of the turbine design, leading to improved performance and cost reductions. Using CO 2 as operating fluid for a radial inflow turbine creates new design, new operating and new modelling challenges. These include mean-line design with enhancing loss models suitable for large dense gas, non-ideal gas behaviour within the blade channel and blade geometry optimisations. Since the supercritical CO 2 has a larger density than the steam or air at the same condition, it might not be adequate to use the well developed loss model to conduct the mean-line design of the whole stage. Since the flow phenomena within the blade channels are complex, involving fluid flow, shock wave position, boundary layer separation, use of the ideal gas model to predict the performance of the turbine might not be adequate. To address these issues, the enhanced one-dimensional loss models, a non-ideal compressible fluid dynamics Riemann solver, and a stator geometry optimiser are developed to create insight on the flow dynamics of supercritical CO 2 radial inflow turbines. The mean-line design results, nonideal compressible fluid dynamics Riemann solver development and stator geometry optimisation are described in details next. The first part aims to provide new insight towards the design of radial turbines for operation with sCO 2 in the 100 kW to 200 kW range. The quasi one-dimensional (1D) mean-line design code TOP-GEN is enhanced to explore and map the radial turbine design space. This mapping process over a state space defined by Head and Flow coefficients allows the selection of an optimum turbine design, while balancing performance and geometrical constraints. By considering three operating points with varying power levels and rotor speeds the effect of these on feasible design space and performance is explored. This provides new insight towards the key geometric features and operational constraints that limit the design space as well as scaling effects. Finally review of the loss breakdown of the designs elucidates the importance of the respective loss mechanisms. Similarly it allows the identification of a design directions that lead to improved performance. Overall this work shows that turbine design with efficiencies in the range 78 % to 82 % are possible in this power range and provides insight into the design space that allows the selection of optimum designs. Next, a new solver for OpenFOAM for non-ideal compressible fluid dynamics is developed. The new solver uses a real-gas Riemann solver, which is based on look-up tables to capture real gas properties. This is achieved by the addition of a new thermodynamic library tightly coupled with the OpenFOAM library. For the solver, the HLLC ALE flux calculator has been modifi...

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“…The facility is of a 10 kWe scale. Further demonstration units of smaller scale have been tested by Korea Institute of Energy Research (KIER) [40,41]. A demonstration facility of a 10 kWe scale exists in Japan at Tokyo Institute of Technology (TIT) with the involvement of several other research institutes [42].…”

Section: Radial Inflow Turbine Prototypesmentioning

confidence: 99%

On the design of small to medium scale radial inflow turbines for supercritical CO2 power cycles

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In rural Australia, concentrating solar power at sub 10 MWe scale is a candidate technology to displace current fossil fuel based technologies [1]. For concentrating solar power to be competitive for this application, coupling with an advanced power cycle is essential. A candidate is the supercritical CO 2 Brayton cycle, which is suitable for higher turbine inlet temperature operation, and has the potential to exceed the efficiency of the steam Rankine cycle. Furthermore, due to lower volumetric flow variation over the cycle, simpler turbomachinery may be used, which enables the cycle to be downscaled while maintaining turbomachinery and cycle efficiency. Of the constituent components in the cycle, turbine efficiency has the greatest impact on cycle efficiency [2]. Radial turbomachinery is a key technology for energy conversion in the supercritical CO 2 Brayton cycle at small scales (i.e. below 30 MW shaft power). While the design of efficient turbines for the supercritical CO 2 Brayton cycle is critical to realising efficient concentrating solar power plants, only a limited number of prototypes have been tested, and none at representative inlet conditions. Radial inflow supercritical CO 2 turbines are characterised by small dimensional scale and high shaft speeds. Prototype turbine designs are characterised by low expansion ratio and medium specific speed to accommodate mechanical restrictions on shaft speed. Medium specific speed designs are selected for prototypes designs due to their implied optimal efficiency. Demonstration test facilities have utilised multiple stages, or lower expansion ratio cycles in order to accommodate designs of this specific speed without exceeding mechanical limits. Increasing inlet conditions to representative cycle conditions for concentrating solar power applications will require higher shaft speeds, or additional stages if specific speed of the stage is to be maintained. Alternatively, the use of single stage low specific speed designs may pose a feasible alternative, however these designs are generally disregarded owing to the implied efficiency penalties shown on gas turbine derived architecture selection charts. Better understanding of loss characteristics of low specific speed supercritical CO 2 turbomachinery is required in order to make an assessment on the feasibility of single stage expansions. Further to sizing of the stator and rotor, stage design also includes components upstream and downstream of the rotor. The broadest challenge for supercritical CO 2 turbomachinery is designing components within a system for high pressure, high density, high temperature, and high shaft speed operation. These constraints may have significant impact on the geometry of these hot gas path features. Details of these features are not clearly detailed in published prototype designs. Considering the knowledge gap for supercritical CO 2 turbines, one key aim of this thesis is to quantify the performance of low specific speed radial inflow turbines using numerical methods. A further aim is t...

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Development of the Supercritical Carbon Dioxide Power Cycle Experimental Loop in KIER

Cited by 34 publications

References 0 publications

Development of the turbomachinery for the supercritical carbon dioxide power cycle

Development of the turbomachinery for the supercritical carbon dioxide power cycle

Development and application of simulation tools for supercritical carbon dioxide radial inflow turbine

On the design of small to medium scale radial inflow turbines for supercritical CO2 power cycles

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