Automatic Numerical Analyses and Optimization of Operating Maps Applied to a Radial Compressor

2019 ◽  
Author(s):  
Markus Wagner ◽  
Johannes Einzinger ◽  
Oliver Velde ◽  
Ralf Lampert
Keyword(s):  
Mass Flow ◽  
Design Space ◽  
Pressure Ratio ◽  
Input Parameter ◽  
Parameter Range ◽  
Maximum Efficiency ◽  
Optimized Design ◽  
Cfd Simulations ◽  
Radial Compressor ◽  
Automated Generation

Abstract This paper contributes to the field of radial compressor design by proposing an adaptive, automated workflow incorporating the analysis of the compressor performance for a multitude of operation points by means of the respective operating maps. Most state-of-the-art approaches do not consider that the operating map limits are not conserved while changing geometric parameters which constraints these analyses to a rather small design space. In contrast, the presented methodology considers the varying operating map limits in regards to the corresponding mass flow and with that expands the possible input parameter range. The presented workflow integrates different software solutions, starting with the automated generation of the compressor geometry based on a parametric CAD model. For each geometry a mesh is generated that is used for all subsequent CFD simulations which finally result in the operating map. For every speed line, the choke point is identified by an adaptive CFD computation (based on the principle of similarity). By using the calculated choke mass flow, supplementary CFD simulations obtain additional operating points on the current speed line by a stepwise reduction of the mass flow. However, the identification of the surge line is not within the scope of the presented approach. Therefore, the range covered by the map is determined by the mass flow at the maximum efficiency and the mass flow at the choke line. The developed framework is applied to optimize the operating map of a radial compressor. A successful optimization shows that the optimized design has an enlarged choke mass flow for lower compressor speed while the pressure ratio and polytropic efficiency are comparable. At the same time, this design has a comparable choke mass flow and efficiency for higher compressor speed, but an improved maximal pressure ratio. The obtained results from the optimization show that the methodology is applicable to a wide parameter range. By adaptively calculating the operating map limits, the approach is not restricted to a small design space.

Using Optimization in Industrial Multi-Point Radial Compressor Design: Map Correction

2019 ◽  
Author(s):  
Edward P. Childs ◽  
Dimitri Deserranno ◽  
Akshay Bagi
Keyword(s):  
Mass Flow ◽  
Static Pressure ◽  
Pressure Ratio ◽  
Base Case ◽  
Design Specification ◽  
Radial Compressor ◽  
Surrogate Based Optimization ◽  
Compressor Design ◽  
Mass Flow Rates ◽  
Operating Points

Abstract The application of Surrogate-Based Optimization (SBO) to the industrial design process for a radial compressor with two operating points is described. The design specification includes two operating points at mass flow rates differing by a factor of three, and efficiency and pressure ratio targets for each point. The base case, while roughly sized from 1D analysis, fails to achieve the pressure ratio targets. In this paper, the optimization focusses on correcting the two speed-line map of total to static pressure ratio vs. mass flow rate. “Smart parameterization”, combining independent and dependent geometric parameters, and yielding reasonable geometries for most input combinations, coupled with efficient SBO, with separate models for response surface modeling and failure prediction, yields a design achieving the targets in just 57 CFD runs. FINE/Turbo [1] is used as the CFD analysis code and FINE/Design3D [2] and MINAMO [3] as the multi-objective optimizer.

Effect of swirl on the performance and stability of transonic axial compressor

2017 ◽  
Vol 232 (6) ◽  
pp. 608-621
Author(s):  
Baofeng Tu ◽  
Luyao Zhang ◽  
Jun Hu
Keyword(s):  
Mass Flow ◽  
Total Pressure ◽  
Pressure Ratio ◽  
Axial Compressor ◽  
Maximum Efficiency ◽  
Stable Boundary ◽  
Tip Leakage ◽  
Stable Operating ◽  
Swirl Intensity ◽  
Total Pressure Ratio

To investigate the effect of twin swirl and bulk swirl on the performance and stability of a transonic axial compressor, a blade swirl generator was designed and simulated with a transonic single rotor using steady and unsteady numerical calculation methods. The bulk swirl intensity was adjusted by replacing the blades with different camber angles. The twin swirl intensity was decreased by reducing the blade number. The counter-rotating bulk swirl generated a significant drop in both the efficiency and stall margin, and resulted in an increase in the choked mass flow, and total pressure ratio. The co-rotating bulk swirl generated a decrease in the mass flow, total pressure ratio and stable operating range. The counter-rotating bulk swirl resulted in suction surface boundary layer separation beyond 50% of the span-wise height as well as more serious tip leakage blockage. The twin swirl resulted in a decrease in the total pressure ratio, maximum efficiency and stable operating range. The steady and unsteady numerical calculation results were consistent, though some differences were observed in the values. For the steady calculation, the maximum efficiency and choked mass flow decreased by 0.88% and 1.74%, respectively, and the mass flow at the stable boundary increased by 3.92% as compared to the uniform inlet flow at twin swirl intensity of 24°. During the unsteady calculation, the mass flow exhibited an increase of only 2.2% at the stable boundary. Under twin swirl and co-rotating bulk swirl and uniform inlet flow, the leading edge spillage of the tip leakage flow resulted in compressor instability. The counter-rotating bulk swirl changed the mechanism of instability. The characterisation of the swirl distortion presented a difference between the steady and unsteady calculations near the stable boundary. The unsteady calculation exhibited a lower mass flow at the stable boundary point and a higher total pressure ratio.

Active Stabilization of Centrifugal Compressor Using Adjustable Geometry Impeller

2001 ◽  
Author(s):  
K. M. Saad Eldin
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
High Speed ◽  
Characteristic Curve ◽  
Pressure Ratio ◽  
Rotating Stall ◽  
Maximum Efficiency ◽  
Impeller Blade ◽  
Stable Regime

Abstract Recent work has shown that variable impeller geometry of the centrifugal compression system can be actively stabilized against the instability known as surge, thereby realizing a significant gain in system mass flow rate. In this context, the paper presents an experimental study about the influence of the impeller blade configuration on the extension of the stabilized characteristic margin beyond the natural surge line and enlarge the usable compressor operating region. This method is estimated from the two major control methods which: surge avoidance control and surge suppression control. The impeller of tandem type with zero overlap is found to be a good sample to satisfy the above concept. The impeller is working as full bladed at stable regime, but it could be transferred into tandem bladed when the mass flow rate decreases below a certain minimum value, just before rotating stall occurs. The operating point moves downwards to another characteristic curve belonging to the new configuration, which has a surge margin less than the original one by 56 percent, at high speed. Herein the effect of tandem shift angle on extending the stabilized range is studied experimentally and a control criterion is suggested. The pressure ratio at the new characteristic curve is decreased by about 3 percent and maximum efficiency is decreased also by about 28 percent.

Optimized Design of Wastewater Disinfection Reactors Based on an Artificial Neural Network Metamodel

2016 ◽  
Author(s):  
Wangshu Wei ◽  
Charles N. Haas ◽  
Bakhtier Farouk
Keyword(s):  
Wastewater Treatment ◽  
Design Space ◽  
Sampling Technique ◽  
Optimized Design ◽  
Hydraulic Characteristics ◽  
Cfd Simulations ◽  
Performance Space ◽  
Wastewater Disinfection ◽  
Treatment Facilities ◽  
Computational Fluid Dynamics Cfd

Peracetic acid (PAA) is an emerging disinfectant for the treatment of wastewater. While it would be possible to optimize the design of this system using computational fluid dynamics (CFD), the computational intensity would be high. As an alternative, we show that an Artificial Neutral Network (ANN) based metamodel can approximate the CFD solutions over an 11 dimensional performance space (dimensions, hydraulic characteristics, and chemical kinetics). By sampling the design space using a quasi-random sampling technique, a series of CFD simulations of disinfection characteristics of PAA in a wastewater treatment reactor are carried out. After a training process using 40 different CFD runs are completed, the ANN developed can be used to achieve an optimized design of wastewater treatment facilities with minimal total cost and acceptable disinfection performance efficiency.

scholarly journals Genetic Algorithm Optimization of the Volute Shape of a Centrifugal Compressor

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Martin Heinrich ◽  
Rüdiger Schwarze
Keyword(s):  
Numerical Model ◽  
Centrifugal Compressor ◽  
Total Pressure ◽  
Pressure Ratio ◽  
Pressure Rise ◽  
Maximum Efficiency ◽  
Algorithm Optimization ◽  
Cross Sectional ◽  
Design Variables ◽  
Design Speed

A numerical model for the genetic optimization of the volute of a centrifugal compressor for light commercial vehicles is presented. The volute cross-sectional shape is represented by cubic B-splines and its control points are used as design variables. The goal of the global optimization is to maximize the average compressor isentropic efficiency and total pressure ratio at design speed and four operating points. The numerical model consists of a density-based solver in combination with the SSTk-ωturbulence model with rotation/curvature correction and the multiple reference frame approach. The initial validation shows a good agreement between the numerical model and test bench measurements. As a result of the optimization, the average total pressure rise and efficiency are increased by over1.0%compared to the initial designs of the optimization, while the maximum efficiency rise is nearly 2.5% atm˙corr=0.19 kg/s.

Dynamic Optimization of an Evaporator by a Nonlinear Model Predictive Controller for Operation at Modular Micro Rectification

2009 ◽  
Author(s):  
Ralf Knauss ◽  
Lukas E. Wiesegger ◽  
Rolf Marr ◽  
Ju¨rgen J. Brandner
Keyword(s):  
Mass Flow ◽  
Dynamic Optimization ◽  
Nonlinear Model ◽  
Process Models ◽  
Maximum Efficiency ◽  
Local Optimum ◽  
Outlet Temperature ◽  
Time Step ◽  
Unit Operations ◽  
Vapor Fraction

Arranging micro-structured equipment to plants whole production processes can be realized with maximum efficiency in tightest space. Unit operations are thereby represented as individual functional modules in shape of micro devices. In a multi unit operation plant a correspondingly large number of manipulable variables have to be coordinated. Due to the design of micro-scaled devices plants form sophisticated systems, while for a fully optimized control still no common satisfying solutions exist. A system of modular, discontinuous phase contacting, micro rectification consists of unit operations heating, cooling, mixing and separating. Heat exchangers, mixers and cyclones for phase separation can be arranged to a counter-current rectification system with maximum mass-transfer efficiency every unit. Operating an electrical heated evaporator for modular rectification purposes a strong coupling of mass flow with the vapor fraction and the outlet temperature can be observed [4]. Operating at a predefined state for mass flow, temperature and vapor fraction may only be possible with difficulties using traditional methods of linear control technology. For dynamic optimization of the multivariable micro-structured evaporator principle of Nonlinear Model Predictive Control (NMPC) was generically formulated in C++ and implemented to LABVIEW 7. Every discrete time step an objective function is generated from nonlinear process models in the form of grouped NARX-polynomials. Optimal sequences of control actions for plant operation are evolved. The resulting constrained cost function is non-convex making detection of relative local optimum a difficult task. This obstacle can be gone around using heuristic optimization algorithm in combination with traditional techniques. Based on experimental results it was demonstrated that NMPC keeps the coupled variables mass flow and temperature energy saving with minimal control activity in the entire two-phase region on their set-points.

Turbocharger-Design Effects on Gasoline-Engine Performance

2005 ◽  
Vol 127 (3) ◽  
pp. 525-530 ◽  
Author(s):  
Theodosios Korakianitis ◽  
T. Sadoi
Keyword(s):  
Steady Flow ◽  
Mass Flow ◽  
Gasoline Engine ◽  
Pressure Ratio ◽  
Engine Performance ◽  
Thermodynamic Cycle ◽  
Final Choice ◽  
Design Point ◽  
Theoretical Considerations ◽  
Flow Experiments

Specification of a turbocharger for a given engine involves matching the turbocharger performance characteristics with those of the piston engine. Theoretical considerations of matching turbocharger pressure ratio and mass flow with engine mass flow and power permits designers to approach a series of potential turbochargers suitable for the engine. Ultimately, the final choice among several candidate turbochargers is made by tests. In this paper two types of steady-flow experiments are used to match three different turbochargers to an automotive turbocharged-intercooled gasoline engine. The first set of tests measures the steady-flow performance of the compressors and turbines of the three turbochargers. The second set of tests measures the steady-flow design-point and off-design-point engine performance with each turbocharger. The test results show the design-point and off-design-point performance of the overall thermodynamic cycle, and this is used to identify which turbocharger is suitable for different types of engine duties.

Performance of Strongly Bowed Stators in a Four-Stage High-Speed Compressor

2004 ◽  
Vol 126 (3) ◽  
pp. 333-338 ◽  
Author(s):  
Axel Fischer ◽  
Walter Riess ◽  
Joerg R. Seume
Keyword(s):  
Mass Flow ◽  
High Speed ◽  
Static Pressure ◽  
Pressure Ratio ◽  
Axial Compressor ◽  
Pressure Rise ◽  
Maximum Pressure ◽  
Controlled Diffusion ◽  
Stage 4 ◽  
The University

The FVV sponsored project “Bow Blading” (cf. acknowledgments) at the Turbomachinery Laboratory of the University of Hannover addresses the effect of strongly bowed stator vanes on the flow field in a four-stage high-speed axial compressor with controlled diffusion airfoil (CDA) blading. The compressor is equipped with more strongly bowed vanes than have previously been reported in the literature. The performance map of the present compressor is being investigated experimentally and numerically. The results show that the pressure ratio and the efficiency at the design point and at the choke limit are reduced by the increase in friction losses on the surface of the bowed vanes, whose surface area is greater than that of the reference (CDA) vanes. The mass flow at the choke limit decreases for the same reason. Because of the change in the radial distribution of axial velocity, pressure rise shifts from stage 3 to stage 4 between the choke limit and maximum pressure ratio. Beyond the point of maximum pressure ratio, this effect is not distinguishable from the reduction of separation by the bow of the vanes. Experimental results show that in cases of high aerodynamic loading, i.e., between maximum pressure ratio and the stall limit, separation is reduced in the bowed stator vanes so that the stagnation pressure ratio and efficiency are increased by the change to bowed stators. It is shown that the reduction of separation with bowed vanes leads to a increase of static pressure rise towards lower mass flow so that the present bow bladed compressor achieves higher static pressure ratios at the stall limit.

Receiver Outlet Temperature Control for Falling Particle Receiver Applications

2021 ◽  
Author(s):  
Nathan Schroeder ◽  
Henk Laubscher ◽  
Brantley Mills ◽  
Clifford K. Ho
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Temperature Rise ◽  
Pid Controller ◽  
Input Parameter ◽  
Slide Gate ◽  
Process Variable ◽  
Test Facility ◽  
Outlet Temperature

Abstract Falling particle receivers (FPRs) are being studied in concentrating solar power applications to enable high temperatures for supercritical CO2 (sCO2) Brayton power cycles. The falling particles are introduced into the cavity receiver via a linear actuated slide gate and irradiated by concentrated sunlight. The thickness of the particle curtain associated with the slide-gate opening dimension dictates the mass flow rate of the particle curtain. A thicker, higher mass flow rate, particle curtain would typically be associated with a smaller temperature rise through the receiver, and a thinner, lower mass flow rate, particle curtain would result in a larger temperature rise. Using the receiver outlet temperature as the process variable and the linear actuated slide gate as the input parameter a proportional, integral, and derivative (PID) controller was implemented to control the temperature of the particles leaving the receiver. The PID parameters were tuned to respond in a quick and stable manner. The PID controlled slide gate was tested using the 1 MW receiver at the National Solar Thermal Test Facility (NSTTF). The receiver outlet temperature was ramped from ambient to 800°C then maintained at the setpoint temperature. After reaching a steady-state, perturbations of 15%–20% of the initial power were applied by removing heliostats to simulate passing clouds. The PID controller reacted to the change in the input power by adjusting the mass flow rate through the receiver to maintain a constant receiver outlet temperature. A goal of ±2σ ≤ 10°C in the outlet temperature for the 5 minutes following the perturbation was achieved.

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