scholarly journals Design of a Tandem Compressor for the Electrically-Driven Turbocharger of a Hybrid City Car

Proceedings ◽  
2020 ◽  
Vol 58 (1) ◽  
pp. 24
Author(s):  
Nicolò Cuturi ◽  
Enrico Sciubba
Keyword(s):  
Energy Recovery ◽  
Gasoline Engine ◽  
Rotor Blades ◽  
Battery Pack ◽  
Net Energy ◽  
Cfd Simulations ◽  
Design Data ◽  
Intermediate Point ◽  
Surge Line ◽  
Operating Points

Within a broader national project aimed at the hybridization of a standard city car (the 998 cc Mitsubishi-derived gasoline engine of the Smart W451), our team tackled the problem of improving the supercharger performance and response. The design concept is that of eliminating the mechanical connection between the compressor and the turbine. It turned out that it is also possible to modify both components to extract extra power from the engine and to use it to recharge the battery pack. First, the initial configuration was analyzed on the basis of the design data provided by the manufacturer. Then, a preliminary performance assessment of the turbocharged engine allowed us to identify three “typical” operating points that could be used to properly redesign the turbomachinery. It was decided to maintain the radial configuration for both turbine and compressor, but to redesign the latter by adding an inducer. For the turbine, only minor modifications to the NGV and rotor blades shape were deemed necessary. Fully 3-D CFD simulations of the rotating machines were performed to assess their performance at three operating points: the kick-in point of the original turbo (2000 rpm), the maximum power regime (5500 rpm) and an intermediate point (3500 rpm) close to the minimum specific fuel consumption (SFC) for the original engine. The results presented in this paper demonstrate that the efficiency of the compressor is noticeably improved for steady operation at all three operating points, and that its choking characteristics have been improved, while its surge line has not been appreciably affected. The net energy recovery was also calculated, and demonstrated interesting returns in terms of storable energy in the battery pack.

scholarly journals Design of a Tandem Compressor for the Electrically-Driven Turbocharger of a Hybrid City Car

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2890
Author(s):  
Nicolò Cuturi ◽  
Enrico Sciubba
Keyword(s):  
Gasoline Engine ◽  
Rotor Blades ◽  
Battery Pack ◽  
Net Energy ◽  
Design Data ◽  
Intermediate Point ◽  
Dynamics Simulations ◽  
Nozzle Guide ◽  
Nozzle Guide Vanes ◽  
Operating Points

Within a broader national project aimed at the hybridization of a standard city car (the 998 cc Mitsubishi-derived gasoline engine of the Smart W451), our team tackled the problem of improving the supercharger performance and response. The originally conceived design innovation was that of eliminating the mechanical connection between the compressor and the turbine. In the course of the study, it turned out that it is also possible to modify both components to extract extra power from the engine and to use it to recharge the battery pack. This required a redesign of both compressor and turbine. First, the initial configuration was analyzed on the basis of the design data provided by the manufacturer. Then, a preliminary performance assessment of the turbocharged engine allowed us to identify three “typical” operating points that could be used to properly redesign the turbomachinery. It was decided to maintain the radial configuration for both turbine and compressor, but to redesign the latter by adding an inducer. For the turbine, only minor modifications to the nozzle guide vanes (NGV) and rotor blades shape were deemed necessary, while a more substantial modification was in order for the compressor. Fully 3-D computational fluid dynamics simulations of the rotating machines were performed to assess their performance at three operating points: the kick-in point of the original turbo (2000 rpm), the maximum power regime (5500 rpm), and an intermediate point (3500 rpm) close to the minimum specific fuel consumption for the original engine. The results presented in this paper demonstrate that the efficiency of the compressor is noticeably improved for steady operation at all three operating points, and that its choking characteristics have been improved, while its surge line has not been appreciably affected. The net energy recovery was also calculated and demonstrated interesting returns in terms of storable energy in the battery pack.

Analysis of Turbofan Performance Under Total Pressure Distortion at Various Operating Points

2015 ◽  
Author(s):  
David B. Weston ◽  
Steven E. Gorrell ◽  
Matthew L. Marshall ◽  
Carol V. Wallis
Keyword(s):  
Total Pressure ◽  
Operating Conditions ◽  
Rotor Blades ◽  
Cfd Simulations ◽  
Blade Loading ◽  
Distortion Analysis ◽  
Work Input ◽  
Total Temperature ◽  
Computational Fluid Dynamics Cfd ◽  
Operating Points

Inlet distortion is an important consideration in fan performance. The focus of this paper is a series of high-fidelity time accurate Computational Fluid Dynamics (CFD) simulations of a multistage fan at choke, design, and near stall operating conditions. These investigate distortion transfer and generation as well as the underlying flow physics of these phenomena under different operating conditions. The simulations are performed on the full annulus of a 3 stage fan and are analyzed. The code used to carry out these simulations is a modified version of OVERFLOW 2.2. The inlet is specified as a 1/rev total pressure distortion. Analysis includes the phase and amplitude of total temperature and pressure distortion through each stage of the fan and blade loading. The total pressure distortion does not change in severity through the fan, but the peak pressure distortion rotates by as much as 45° at the near stall point. This is due to a variation in the work input around the blades of the rotor. This variation is also responsible for the generation of total temperature distortion in the fan. The rotation of the total temperature distortion becomes more pronounced as the fan approaches stall, and the total temperature distortion levels increase. The amount of work performed by a single blade can vary by as much as 25% in the first stage at near stall. The variation in work becomes more pronounced as the fan approaches stall. The passage shock in the rotor blades moves nearly 20% of the blade chord in both the peak efficiency and near stall cases.

scholarly journals Multi-Country Scale Assessment of Available Energy Recovery Potential Using Micro-Hydropower in Drinking, Pressurised Irrigation and Wastewater Networks, Covering Part of the EU

Water ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 899
Author(s):  
Djordje Mitrovic ◽  
Miguel Crespo Chacón ◽  
Aida Mérida García ◽  
Jorge García Morillo ◽  
Juan Antonio Rodríguez Diaz ◽  
...  
Keyword(s):  
Drinking Water ◽  
Northern Ireland ◽  
Energy Recovery ◽  
Large Scale ◽  
Significant Proportion ◽  
Value Added ◽  
Cost Effective ◽  
Net Energy ◽  
Water Networks ◽  
Scale Assessment

Studies have shown micro-hydropower (MHP) opportunities for energy recovery and CO2 reductions in the water sector. This paper conducts a large-scale assessment of this potential using a dataset amassed across six EU countries (Ireland, Northern Ireland, Scotland, Wales, Spain, and Portugal) for the drinking water, irrigation, and wastewater sectors. Extrapolating the collected data, the total annual MHP potential was estimated between 482.3 and 821.6 GWh, depending on the assumptions, divided among Ireland (15.5–32.2 GWh), Scotland (17.8–139.7 GWh), Northern Ireland (5.9–8.2 GWh), Wales (10.2–8.1 GWh), Spain (375.3–539.9 GWh), and Portugal (57.6–93.5 GWh) and distributed across the drinking water (43–67%), irrigation (51–30%), and wastewater (6–3%) sectors. The findings demonstrated reductions in energy consumption in water networks between 1.7 and 13.0%. Forty-five percent of the energy estimated from the analysed sites was associated with just 3% of their number, having a power output capacity >15 kW. This demonstrated that a significant proportion of energy could be exploited at a small number of sites, with a valuable contribution to net energy efficiency gains and CO2 emission reductions. This also demonstrates cost-effective, value-added, multi-country benefits to policy makers, establishing the case to incentivise MHP in water networks to help achieve the desired CO2 emissions reductions targets.

Compressor Design for Multi-Point Operating Conditions of Turbocharged Gasoline Engines

2010 ◽  
Author(s):  
Tao Chen ◽  
Yangjun Zhang ◽  
Xinqian Zheng ◽  
Weilin Zhuge
Keyword(s):  
Internal Combustion Engines ◽  
Gasoline Engine ◽  
Design Method ◽  
Pressure Ratio ◽  
Operating Conditions ◽  
Combustion Engines ◽  
Gasoline Engines ◽  
Compressor Design ◽  
Operating Points ◽  
Load Conditions

Turbocharger compressor design is a major challenge for performance improvement of turbocharged internal combustion engines. This paper presents a multi-point design methodology for turbocharger centrifugal compressors. In this approach, several design operating condition points of turbocharger compressor are considered according to total engine system requirements, instead of one single operating point for traditional design method. Different compressor geometric parameters are selected and investigated at multi-point operating conditions for the flow-solutions of different design objectives. The method has been applied with success to a small centrifugal compressor design of a turbocharged gasoline engine. The results show that the consideration of several operating points is essential to improve the aerodynamic behavior for the whole working range. The isentropic efficiency has been increased by more than 5% at part-load conditions while maintaining the pressure ratio and flow range at full-load conditions of the gasoline engine.

scholarly journals Predicting Cycle-to-Cycle Variation With Concurrent Cycles in a Gasoline Direct Injected Engine With Large Eddy Simulations

2018 ◽  
Author(s):  
Daniel Probst ◽  
Sameera Wijeyakulasuriya ◽  
Eric Pomraning ◽  
Janardhan Kodavasal ◽  
Riccardo Scarcelli ◽  
...  
Keyword(s):  
Gasoline Engine ◽  
Direct Injection ◽  
Engine Performance ◽  
Turnaround Time ◽  
Operating Conditions ◽  
Gasoline Direct Injection ◽  
Cycle Variation ◽  
Spark Timing ◽  
Large Eddy ◽  
Operating Points

High cycle-to-cycle variation (CCV) is detrimental to engine performance, as it leads to poor combustion and high noise and vibration. In this work, CCV in a gasoline engine is studied using large eddy simulation (LES). The engine chosen as the basis of this work is a single-cylinder gasoline direct injection (GDI) research engine. Two stoichiometric part-load engine operating points (6 BMEP, 2000 RPM) were evaluated: a non-dilute (0% EGR) case and a dilute (18% EGR) case. The experimental data for both operating conditions had 500 cycles. The measured CCV in IMEP was 1.40% for the non-dilute case and 7.78% for the dilute case. To estimate CCV from simulation, perturbed concurrent cycles of engine simulations were compared to consecutively obtained engine cycles. The motivation behind this is that running consecutive cycles to estimate CCV is quite time-consuming. For example, running 100 consecutive cycles requires 2–3 months (on a typical cluster), however, by running concurrently one can potentially run all 100 cycles at the same time and reduce the overall turnaround time for 100 cycles to the time taken for a single cycle (2 days). The goal of this paper is to statistically determine if concurrent cycles, with a perturbation applied to each individual cycle at the start, can be representative of consecutively obtained cycles and accurately estimate CCV. 100 cycles were run for each case to obtain statistically valid results. The concurrent cycles began at different timings before the combustion event, with the motivation to identify the closest time before spark to minimize the run time. Only a single combustion cycle was run for each concurrent case. The calculated standard deviation of peak pressure and coefficient of variance (COV) of indicated mean effective pressure (IMEP) were compared between the consecutive and concurrent methods to quantify CCV. It was found that the concurrent method could be used to predict CCV with either a velocity or numerical perturbation. A large and small velocity perturbation were compared and both produced correct predictions, implying that the type of perturbation is not important to yield a valid realization. Starting the simulation too close to the combustion event, at intake valve close (IVC) or at spark timing, under-predicted the CCV. When concurrent simulations were initiated during or before the intake even, at start of injection (SOI) or earlier, distinct and valid realizations were obtained to accurately predict CCV for both operating points. By simulating CCV with concurrent cycles, the required wall clock time can be reduced from 2–3 months to 1–2 days. Additionally, the required core-hours can be reduced up to 41%, since only a portion of each cycle needs to be simulated.

Kraft-Mill Biosolids Treatment by Conventional and Biphasic Fermentation

1999 ◽  
Vol 40 (11-12) ◽  
pp. 169-177 ◽  
Author(s):  
S. Ghosh ◽  
D. C. Taylor
Keyword(s):  
Energy Recovery ◽  
Single Stage ◽  
High Rate ◽  
Net Energy ◽  
Municipal Sludge ◽  
Nutrient Source ◽  
Two Phase ◽  
Fuel Gas ◽  
Reduction Efficiency ◽  
Nitrogen Phosphorus

Kraft primary and mixed primary-activated sludges were gasified by thermophilic (50 °C) high-rate and mesophilic two-phase digestion. Kraft sludges were deficient in nitrogen, phosphorus, and other unidentified nutrients. Municipal sludge proved to be a much better nutrient source than inorganic salts. Performance of the mesophilic (35°C), two-phase anaerobic digestion (TPAD) system was about the same as that of thermophilic single-stage, high-rate digestion at a 10-day HRT as judged in terms of methane yield (0.17 SCM/kg VS added) and VS reduction efficiency (43%). The mesophilic TPAD process yielded a higher methane-content (65%) fuel gas; it is capable of exhibiting higher net-energy recovery efficiency than thermophilic single-stage digestion.

Improving Accuracy and Comparability of Turbocharger Performance Measurements

2019 ◽  
Author(s):  
Mario Schinnerl ◽  
Mathias Bogner ◽  
Jan Ehrhard
Keyword(s):  
Turbine Stage ◽  
Performance Measurements ◽  
Cfd Simulations ◽  
Operating Range ◽  
Turbine Efficiency ◽  
Run Up ◽  
Improving Accuracy ◽  
Compressor Power ◽  
The Impact ◽  
Operating Points

Abstract The reduction of fuel consumption and emissions is the most dominant challenge in powertrain development. Therefore, engine and turbocharger have to be matched with high accuracy to achieve optimum powertrain efficiencies. With respect to relevant engine operating points, compressor maps can be measured in full operating range on a standard hot gas test bench. Even though there is no need for extrapolation of the operating range, they have to be corrected for the impact of heat transfer to represent the adiabatic performance of the compressor stage. The common approach to evaluate the turbine efficiency is to apply the energy balance of the entire turbocharger where the turbine power is the sum of the compressor power and the friction losses of the radial and axial journal bearings. The adiabatic compressor power in combination with the calculation of the friction losses by using validated run-up simulations enables the evaluation of the isentropic turbine efficiency and the comparability to CFD simulations of the turbine stage. For reasons of comparability to CFD simulations, which can predict a wide operating range of the turbine stage, the limited measureable turbine operating range is enhanced by a so-called compressor closed loop unit (CCLU). This additional test device enables to vary the demand of compressor power for the same operating points as in the standard mapping and therefore to enlarge the measureable turbine operating range. In combination with proper extrapolation methods, the isentropic turbine efficiency can now be compared to CFD simulations.

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