Performance improvement of a radial organic Rankine cycle turbine by means of automated computational fluid dynamic design

2013 ◽  
Vol 227 (6) ◽  
pp. 637-645 ◽  
Author(s):  
John Harinck ◽  
David Pasquale ◽  
Rene Pecnik ◽  
Jos van Buijtenen ◽  
Piero Colonna
Keyword(s):  
Performance Improvement ◽  
Computational Fluid Dynamic ◽  
Fluid Dynamic ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Dynamic Design

scholarly journals Design Method and Performance Prediction for Radial-Inflow Turbines of High-Temperature Mini-Organic Rankine Cycle Power Systems

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
Carlo M. De Servi ◽  
Matteo Burigana ◽  
Matteo Pini ◽  
Piero Colonna
Keyword(s):  
Power Systems ◽  
Computational Fluid Dynamic ◽  
Dynamic Models ◽  
Waste Heat ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Loss Models ◽  
Radial Inflow Turbine

The realization of commercial mini organic Rankine cycle (ORC) power systems (tens of kW of power output) is currently pursued by means of various research and development activities. The application driving most of the efforts is the waste heat recovery from long-haul truck engines. Obtaining an efficient mini radial inflow turbine, arguably the most suitable type of expander for this application, is particularly challenging, given the small mass flow rate, and the occurrence of nonideal compressible fluid dynamic effects in the stator. Available design methods are currently based on guidelines and loss models developed mainly for turbochargers. The preliminary geometry is subsequently adapted by means of computational fluid-dynamic calculations with codes that are not validated in case of nonideal compressible flows of organic fluids. An experimental 10 kW mini-ORC radial inflow turbine will be realized and tested in the Propulsion and Power Laboratory of the Delft University of Technology, with the aim of providing measurement datasets for the validation of computational fluid dynamics (CFD) tools and the calibration of empirical loss models. The fluid dynamic design and characterization of this machine is reported here. Notably, the turbine is designed using a meanline model in which fluid-dynamic losses are estimated using semi-empirical correlations for conventional radial turbines. The resulting impeller geometry is then optimized using steady-state three-dimensional computational fluid dynamic models and surrogate-based optimization. Finally, a loss breakdown is performed and the results are compared against those obtained by three-dimensional unsteady fluid-dynamic calculations. The outcomes of the study indicate that the optimal layout of mini-ORC turbines significantly differs from that of radial-inflow turbines (RIT) utilized in more traditional applications, confirming the need for experimental campaigns to support the conception of new design practices.

Centrifugal Turbines for Mini-Organic Rankine Cycle Power Systems

2014 ◽  
Vol 136 (12) ◽  
Author(s):  
Emiliano Casati ◽  
Salvatore Vitale ◽  
Matteo Pini ◽  
Giacomo Persico ◽  
Piero Colonna
Keyword(s):  
High Temperature ◽  
Power Systems ◽  
Heat Recovery ◽  
Fluid Dynamic ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Expansion Ratio ◽  
Preliminary Design ◽  
Dynamic Design ◽  
Radial Outflow

Organic Rankine cycle (ORC) power systems are rapidly diffusing as a technology for the conversion of thermal energy sources in the small-to-medium power range, e.g., from 150 kWe up to several MWe. The most critical component is arguably the expander, especially if the power capacity is small or very small, as it is the case for innovative high-potential applications such as waste heat recovery from truck engines, or distributed conversion of concentrated solar radiation. In these so-called high-temperature applications, the expansion ratio is very high; therefore, turbines are the expanders of choice. Recently, multistage radial-outflow turbines (ROT), a nonconventional turbine configuration, have been studied, and first commercial implementations in the MWe power range have been successful. The objective of this work is the evaluation of the radial-outflow arrangement for the turbine of high-temperature mini-ORC power systems, with power output of the order of 10 kWe. To this end, a method for the preliminary fluid-dynamic design is presented. It consists of an automated optimization procedure based on an in-house mean-line code for the one-dimensional preliminary design and efficiency estimation of turbines. It is first shown that usually adopted simplified design procedures, such as that of the so-called repeating-stage, cannot be extended to minicentrifugal turbines. The novel methodology is applied to the exemplary case of the 10 kWe turbine of an ORC power system for truck engine heat recovery documented in the literature. The expansion ratio is 45. The preliminary fluid-dynamic design of two miniturbines is presented, namely, a five-stage transonic and a three-stage slightly supersonic turbine. The outcome of the preliminary design leads to two turbine configurations whose fluid-dynamic efficiency exceeds 79% and 77%, respectively. The speed of revolution is around 12,400 and 15,400 RPM for the five-stage and the three-stage machine, respectively. These results show that the ROT configuration may allow for compact and efficient expanders for low power output applications.

Development of a New Disposable Pulsatile Pump for Cardiopulmonary Bypass: Computational Fluid-Dynamic Design and In Vitro Tests

ASAIO Journal ◽  
2002 ◽  
Vol 48 (3) ◽  
pp. 260-267 ◽  
Author(s):  
Gianfranco B. Fiore ◽  
Alberto Redaelli ◽  
Gualtiero Guadagni ◽  
Fabio Inzoli ◽  
Roberto Fumero
Keyword(s):  
Cardiopulmonary Bypass ◽  
Computational Fluid Dynamic ◽  
Fluid Dynamic ◽  
In Vitro Tests ◽  
Dynamic Design ◽  
Pulsatile Pump

Preliminary Design of the ORCHID: A Facility for Studying Non-Ideal Compressible Fluid Dynamics and Testing ORC Expanders

2016 ◽  
Author(s):  
Adam Joseph Head ◽  
Carlo De Servi ◽  
Emiliano Casati ◽  
Matteo Pini ◽  
Piero Colonna
Keyword(s):  
Power Systems ◽  
Power Output ◽  
Fluid Dynamic ◽  
Supersonic Nozzle ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Operating Conditions ◽  
Performance Estimation ◽  
Preliminary Design ◽  
Integrated Device

Organic Rankine Cycle (ORC) power systems are receiving increased recognition for the conversion of thermal energy when the source potential and/or its temperature are comparatively low. Mini-ORC units in the power output range of 3–50 kWe are actively studied for applications involving heat recovery from automotive engines and the exploitation of solar energy. Efficient expanders are the enabling components of such systems, and all the related developments are at the early research stage. Notably, no experimental gasdynamic data are available in the open literature concerning the fluids and flow conditions of interest for mini-ORC expanders. Therefore, all the performance estimation and the fluid dynamic design methodologies adopted in the field rely on non-validated tools. In order to bridge this gap, a new experimental facility capable of continuous operation is being designed and built at Delft University of Technology, the Netherlands. The Organic Rankine Cycle Hybrid Integrated Device (ORCHID) is a research facility resembling a state-of-the-art high-temperature ORC system. It is flexible enough to treat different working fluids and operating conditions with the added benefit of two interchangeable Test Sections (TS’s). The first TS is a supersonic nozzle with optical access whose purpose is to perform gas dynamic experiments on dense organic flows in order to validate numerical codes. The second TS is a test-bench for mini-ORC expanders of any configuration up to a power output of 100 kWe. This paper presents the preliminary design of the ORCHID setup, discussing how the required operational flexibility was attained. The envisaged experiments of the two TS’s are also described.

scholarly journals Design Methodology for Supersonic Radial Vanes Operating in Nonideal Flow Conditions

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Nitish Anand ◽  
Salvatore Vitale ◽  
Matteo Pini ◽  
Gustavo J. Otero ◽  
Rene Pecnik
Keyword(s):  
Shock Wave ◽  
Fluid Dynamic ◽  
Dynamic Performance ◽  
Computational Cost ◽  
Organic Rankine Cycle ◽  
Suction Side ◽  
Rankine Cycle ◽  
Computational Effort ◽  
Design Guidelines ◽  
Boundary Layer Interaction

The stator vanes of high-temperature organic Rankine cycle (ORC) radial-inflow turbines (RIT) operate under severe expansion ratios and the associated fluid-dynamic losses account for nearly two-thirds of the total losses generated within the blading passages. The efficiency of the machine can strongly benefit from specialized high-fidelity design methods able to provide shapes attenuating shock wave formation, consequently reducing entropy generation across the shock-wave and mitigating shock-wave boundary layer interaction. Shape optimization is certainly a viable option to deal with supersonic ORC stator design, but it is computationally expensive. In this work, a robust method to approach the problem at reduced computational cost is documented. The method consists of a procedure encompassing the method of characteristics (MoC), extended to nonideal fluid flow, for profiling the diverging part of the nozzle. The subsonic section and semibladed suction side are retrieved using a simple conformal geometrical transformation. The method is applied to design a supersonic ORC stator working with Toluene vapor, for which two blade shapes were already available. The comparison of fluid-dynamic performance clearly indicates that the MoC-Based method is able to provide the best results with the lowest computational effort, and is therefore suitable to be used in a systematic manner for drawing general design guidelines.

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