Compressor Inlet Research Articles

Exergoeconomic and sensitivity analyses of a gas turbine power plant using MINI-REFPROP and MATLAB simulink

In this paper, exergy, exergoeconomic, and exergoenvironmental analysis of a gas turbine cycle and its optimization have been carried out by MINI-Reference Fluid Properties (MINI-REFPROP) and Matrix Laboratory (MATLAB) SIMULINK. The parametric study was carried out based on the Specific Exergy Costing approach. The mathematical models were developed and presented regarding mass, energy, and economy. The Excel and MATLAB LIBRARY TOOLS BOX are used to perform thermodynamic properties and research analyses. The analyses lead to valuable economic status benchmarks. The exergoeconomic factor, relative cost, total cost of energy loss, and energy destruction for the combustion chamber and work output were determined. The parametric study was conducted, considering the effects of the gas turbine inlet temperature, air compressor inlet temperature, and compressor pressure ratio. For the considered case study status, the combustion chamber in the plant revealed the highest amount of energy destruction (85%), leading to the recommendation that more attention be paid to boilers in terms of design, selection, operation, and maintenance, while the combustion chamber has a high improvement potential (91%).

Heat Generation Inside Turbocharger Without External Heat Source

Recently, many vehicle manufacturers started to invest in new technology to reduce the emission produced by their engines. Due to the emission regulations that become more stringent and the rising demand for highly efficient vehicles, many new technologies were introduced to achieve the demand. One of the technologies that gain popularity in modern vehicles is applying force induction systems such as turbocharging and supercharging the engine. By using the turbocharger, two major advantages can be achieved which are increasing engine efficiency and engine size reduction. However, turbocharger performance will be affected by the amount of heat that is generated due to friction inside the bearing, air compression process and also the heat transfer from the exhaust gas that has high temperature and pressure. In this paper, the heat generation inside the turbocharger unit without any external heat source was measured and analysed. A turbocharger unit from Garrett Turbocharger where the model is GT2056 was used for this experiment. The operating speed in the study is recorded between 20 000 rpm until 70 000 rpm and the temperature at the turbine inlet and compressor inlet is at room temperature. The parameters that were measured are the temperature difference at the turbine side, bearing housing and also compressor side. From the results obtained, it can be concluded that the bearing housing produces a higher amount of heat compared to the compressor side while the turbine side will experience heat loss.

Investigation of inlet air pressure and evaporative cooling of four different cogeneration cycles

Abstract The objective of this study was to search the effects of the inlet air compressor pressure and evaporative cooling of four different cogeneration plants that are absorption cooling (ab), basic (bsc), air heating (airh), and air fuel heating (airfh) cogeneration systems by using the first law and the second law of thermodynamics, and the exergy analysis methods. For analysis, a program is written by the author in the FORTRAN programming language. Decreasing the atmospheric pressure or increasing the installation altitude of the plants increases the Z factor (ratio of lost exergy to useful exergy) of the four cycles about 10–13%. Also, decreasing inlet air pressure decreases the specific work about 25–28%, and the fuel energy saving ratio of the four cycles decreases about 29–30%. The method of water spray cooling of the compressor inlet air especially in the summer months, the humidity increases and the evaporative cooling can be obtained. By using this method, the ratio of lost exergy to useful exergy can be decreased for the four cycles about 0.5–2%. Also, the specific work of the four cycles can be increased about 1.2–6%.

Experimental Study on a Supercritical CO2 Centrifugal Compressor Used in a MWe Scale Power Cycle

The centrifugal compressor is the core component of supercritical CO2 power cycle, and its performance and operation stability are research hotspots. However, there are few experimental studies, especially for compressors used in Mwe-scale power cycles. In this paper, based on a 1 MWe supercritical CO2 power cycle, a single-stage centrifugal supercritical CO2 compressor is designed with speed of 40,000 RPM, a pressure ratio of 2.5 and a mass flow of 16.3 kg/s. In order to carry out the compressor test, a general experimental platform for MWe sCO2 compressors is built. In the test, the mass flow range is 13.5~18 kg/s and the maximum experimental pressure ratio is close to 2.0. The performance curve of the compressor of 31,000 ± 1000 RPM is obtained, and the historical curve of the experiment is given. Then, the experimental curve is compared with the design curve using a dimensionless method. The isentropic head coefficient of the experimental curve is lower than the design value, and the experimental curves shift towards the boundary of small flow coefficient. Finally, the influence of compressor inlet condensation on compressor performance and the change of operating boundary is preliminarily explained.

Перспективы применения российских абсорбционных термотрансформаторов на ПГУ-ТЭЦ

The electrical power of power plants based on gas turbines (GT) decreases with an increase in air temperature and, as a result, a decrease in its mass flow at the compressor inlet. This makes it relevant to develop methods for increasing air density by lowering its temperature when wor¬king in hot arid regions and regions with a tropical humid climate. To cool the air, it is proposed to use absorption chillers (LBAC). It is shown that for air cooling in a dry hot climate, it is sufficient to use LBAC with single-stage absorption. For a humid tropical climate, where deeper air cooling is required with a simultaneous decrease in its moisture content, it is proposed to use ABCM with two-stage absorption, which are capable of producing cold at negative temperatures. To do this, it is proposed to introduce an additional evaporation and absorption unit with peri¬pheral equipment into the standard industrial design of the LBAC with single-stage absorption. Comparative energy efficiency of LBAC of standard design and LBAC with two-stage absorption during air cooling at the GT compressor inlet has been evaluated. For such critical facilities for the Russian economy as gas pumping stations using gas turbines, an LBAC unit with two-stage absorption and removal of absorption heat by water-circulating cooling systems based on cooling towers, or using air coolers (drycoolers) with the ability to turn off an additional evaporation unit if necessary, is proposed. and absorption.

An Experimental Study to Understand the Effect of Calibration Parameters and Operating Conditions on Piston and Cylinder Bore Temperatures for a Multi-Cylinder DI Diesel Engine through Piston Telemetry

<div class="section abstract"><div class="htmlview paragraph">In a bid to adopt pro-active strategies to reduce pollution, the Indian government decided to leapfrog from current emission norms to the advanced emission regulations like BS VI, CPCB4. The advancement in emission regulation is also accompanied by customer expectation of increased product performance with lower cost. Downsizing of the engines has led base engine components to experience more thermomechanical loads. Lower product cost demand of the market has pushed engineers to understand the system level interactions and identify the levers other than component design changes. Current analytical techniques provide little iteration feasibility to explore all the possible levers. This paper focuses on experimental study to understand the effect of engine operating conditions on piston and bore temperatures. Piston telemetry technique is used in capturing the real time piston temperature data with flexibility to carry out design of experiments. Bore temperatures were measured using thermocouples. Impact of variation in Rail pressure (RP), injection timing (SOI), engine coolant out temperature, delta pressure and temperature across CAC, Compressor inlet temperature (CIT) and turbine outlet pressure (TOP) were studied. Results of main and interaction effects for individual factors are discussed. Engine COT and injection timings identified as major levers showing linear relation. Other parameters were found as a minor contributing factor, even though those are critical in engine performance tuning.</div></div>

Modeling and validation of the volume effect on the axial fan transient performance

Abstract Since Professor Greziter first proposed a theoretical model to predict the dynamic behavior of a compression system in 1976, the contribution of the volume effect to compressor flow instabilities has been widely studied, but the role of volume effect on the compressor performance during acceleration and deceleration has not received much attention. Therefore, starting from the Greitzer lumped parameter approach and integrating with real engine simulated components to improve the Greitzer’s model, an engine transient simulation model accounting for the compressor volume effect (referred to as the unsteady model) is developed in this paper. Based on a real turbofan engine, transient examination comprising acceleration and deceleration has been conducted for the validation of the unsteady model. The simulation results show better agreement with the experimental data compared with the transient simulation without considering the compressor volume effect (referred to as the quasi-steady model), which confirms the importance of introducing the compressor volume effect into the engine transient modeling. And the cause of the deviation between unsteady model and quasi-steady model are further explained by the compressor inlet and outlet mass flow curve. The results may further contribute to the development of engine transient model.

Three-Fluid Nozzle Spray Drying Strategy for Efficient Fabrication of Functional Colloidosomes.

Colloidosomes as Pickering emulsion microcapsules are expected to serve various applications, including encapsulation of drugs and loading of functional materials. Normally, when using colloidosomes for drug encapsulation, the latex particles as shell materials need to be mixed with drugs before the assembly process. However, this procedure may cause aggregation of latex particles, thereby resulting in disordered assembled shells or a low loading efficiency. Herein, we propose a three-fluid nozzle spray drying process to efficiently assemble latex particles of P(styrene (St)-co-butyl acrylate (BA)) into colloidosomes. The three-fluid nozzle spray drying equipment allows for the preparation for drug encapsulation without advance mixing of drug and shell materials. This strategy enables the construction of colloidosomes with uniform and controllable pores and the loading of functional materials. The effects of the compressed air flow rate, inlet temperature, feed rate, and solid content were explored, revealing the formation mechanism of colloidosomes during the spray drying process. Doxycycline hydrochloride (DH) was encapsulated in colloidosomes for controllable release, and the sustained release time is up to 100 h. The release rate can be adjusted by varying the glass transition temperature (Tg) and size of latex particles. Furthermore, Fe3O4 nanoparticle (NP)-loaded colloidosomes were constructed by this strategy. The magnetic response intensity of colloidosomes can be modulated by varying the amount of Fe3O4 NPs. The anticancer drug encapsulation and loading of other functional particles were also explored to expand applications.

Assessment of Variable Geometry Orifice Compressor Technology Impact in a New Generation of Compression Ignition Powertrains at Low-End and Transient Operation

Surge is a phenomenon that limits the operating range of the compressor at low engine speeds and high boost pressure in turbocharged powertrains. This article assesses two prototype turbochargers of variable geometry orifice (VGO) which compensate for the limitation of the boost pressure at low engine speeds. The VGO prototypes modify the inlet compressor section, extending the compressor characteristic map into lower mass flows (surge limit region). The VGO turbochargers analyzed are also both equipped with variable geometry turbine (VGT) technology. The experiments focus on low-end torque operation ranges in steady and transient engine running conditions. The experimental results are used to validate a 1D physical model. From the modelling perspective, a comprehensive study of the VGO-VGT prototypes is assessed. Results reveal the benefits of VGO technology in terms of attaining higher boost pressure, improved compressor efficiency, and overall engine performance at low engine speeds.

Assessment and optimization of a novel waste heat stepped utilization system integrating partial heating sCO2 cycle and ejector refrigeration cycle using zeotropic mixtures for gas turbine

A waste heat stepped utilization system integrating a partial heating sCO2 power cycle and a thermally-driven ejector refrigeration cycle is proposed for gas turbine performance enhancement. The gas turbine exhaust heat is stepped utilized by two gas heaters in the sCO2 power cycle and a waste heater. Then, the exhaust CO2 heat is cascade utilized by the ejector refrigeration cycle using zeotropic mixtures (R245fa/R1234ze) as its working fluid. Detailed energy, exergy, and economic models are built to conduct the system performance investigation. The results show that the proposed system can improve the thermal and exergy efficiency by 28.23% and 2.65% compared with the single sCO2 cycle. The parametric study discloses that there are optimal turbine inlet temperature and compressor inlet pressure for power output and optimal refrigerant mixture ratio, around 0.30, for cooling capacity. Further, multi-objective optimization is implemented, and the overall system efficiency, bottoming system exergy efficiency, and levelized cost of exergy can reach 62.15%, 45.22%, and 0.076 $/kWh, respectively. Finally, to prove the superiority of the integrated system for different application scenarios, the system performance is optimized in the gas turbine part-load. The results reveal that the proposed system can effectively improve the gas turbine performance, especially in the part-load. Under all the gas turbine loads, the proposed system's levelized cost of exergy is no more than 0.076 $/kWh, which provides theoretical references for the development of the gas turbine combined system in practical engineering.

Modeling and analysis of thermodynamic performance of 6F unit based on Thermoflow

With the continuous development of combined cycle technology, mastering the thermal performance of combined cycle unit is beneficial to the system performance analysis, operation optimization and debugging. In this paper, the mathematical model of each component of the gas-steam combined cycle was established. Thermoflow software was used to calculate the thermodynamic performance of the system, and the influence of inlet temperature and gas turbine load on the thermodynamic performance of the system was analyzed. The results show that the model is reliable and the maximum error is 1.47%. When compressor inlet temperature increases by 10°C, gas turbine power decreases by about 5.8% and power generation thermal efficiency decreases by 0.15%. When the gas turbine load decreases by 10%, the thermal efficiency of combined cycle power generation decreases by 1.4%.

A novel water freezing desalination plant integrated into a combined gas power cycle plant

In this work, a freezing desalination unit is integrated into a conventional combined power plant to improve the plant performance and produce desalinated water. A mathematical model is developed to simulate the modified cycle. The effect of compressor inlet air temperature on thermal performance, desalinated water production capacity and specific fuel consumption is examined. Results of the modified cycle were compared to that of the conventional cycle. The results show that the proposed system is capable of producing up to 2.74 million m3of desalinated water annually from a brackish water source (TDS of 2000 mg/l) with an increase in the Energy Utilization Efficiency (EUE) by 15% as compared to the designed value under ISO standard conditions. Furthermore, operation cost for fresh water production is also examined, results show that the fuel cost of 1 m3 of desalinated water varies between (0.56–0.58) $/m3 compared with 0.66 $/m3 and 0.93 $/m3 for desalination technologies of R. O and MED, respectively.

Impact investigation of inlet environmental changes on the rated condition performance of a high-pressure compressor

Abstract The variations of inlet environment parameters can make significant effects on the compressor performance. This paper aims to investigate the effects of inlet total pressure and total temperature changes on the rated condition performance of a nine-stage HPC. Different cases of total pressure and total temperature boundary conditions at this compressor inlet are studied by 3-D numerical simulations with experimental validations. The numerical results confirm that the variations of inlet total pressure and total temperature make different effects on the rated condition performance of compressor. The overall performance parameters, such as the corrected mass flow and isentropic efficiency, will increase with inlet total pressure increasing and decrease with inlet total temperature increasing by different change rules. The flow similarity is also investigated by comparing the calculated results of critical quantities in different cases. The results indicate that the rising inlet total pressure can increase the Reynolds number and it is beneficial to reduce the viscous influence so that it is available to improve the performance; the rising inlet total temperature can decrease both the specific heat ratio and Reynolds number so that it will lead to the compressor performance decline inevitably.

Dynamic characteristics and control strategies of the supercritical CO2 Brayton cycle tailored for the new generation concentrating solar power

The supercritical CO2 (sCO2) Brayton cycle has the advantages of high efficiency, good flexibility and compact equipment, and is widely regarded as the ideal power cycle for the new generation concentrating solar power (CSP). The application scenario of the CSP determines that the unit's fast peak shaving capability must be considered. In this paper, a dynamic simulation model was developed for an indirect-heated 800 °C/550 °C sCO2 CSP test plant, containing a particle heat storage system. The effects of control modes of heating power, cooling power, mass flow rate (m), turbine rotational speed and sCO2 inventory on the system dynamic characteristics were researched. It was found that the control mode of changing particle/water mass flow rate had a significantly faster response speed than changing temperature. Using the turbine optimal rotational speed control mode could improve the net cycle efficiency from 15.30% to 16.12%, in a continuous linear load reduction process. The sCO2 inventory control module played a crucial role in limiting the fluctuation of compressor inlet pressure. The regulation mode of changing m and turbine inlet temperature (T4) synchronously and that of changing m with constant T4 were all proved to achieve the goal of fast peak shaving well, but the latter one was safer, which could greatly limit the temperature change rate of sCO2 and equipment in the fast peak shaving process. Our work not only offers an operation solution for the sCO2 CSP test plant, but also gives guidance for the efficient, flexible and safe design of the third generation CSP plants.

Thermoeconomic optimization of a solar-assisted supercritical CO2 Brayton cycle, organic Rankine cycle and multi-effect distillation system

In this paper, the simulation and optimization of a combined supercritical carbon dioxide Brayton cycle, an organic Rankine cycle and multi-effect distillation system driven by solar energy have been applied for power and freshwater generation. In this cycle, the solar collector, the central receiver reflected the sun’s light by heliostats, enters the storage system and then enters the fluid stream according to the amount of heat required to initiate the cycle. The working fluid of solar receiver is a mixture of the 60% NaNO3 and 40% KNO3, supercritical carbon dioxide is working fluid of the Brayton cycle and R600 is the working fluid of the organic Rankine cycle. The innovation of this article is using power and fresh water cycle without fuel consumption (with solar system and storage tanks). The simulation of this combined cycle was carried out by engineering equation solver software and energy and exergy efficiency changes in terms of different parameters are obtained. Then, a multi objective optimization of this system considering exergy efficiency and cost of system as objective functions is performed by genetic algorithm in Matlab software. Decision variables of the whole cycles are including Compressor inlet temperature, Turbine inlet temperature, Number of MED effect, The temperature of the water fed the desalination, Evaporator pinch point, Mass flow (Critical Carbon Dioxide), Turbine inlet pressure, Compressor inlet pressure and Pressure drop. The two objective functions optimization including exergy and economic parameters of this cycle is carried out for achieving reduction of electricity generation cost and increase of the exergy efficiency. The results of this optimization showed, the maximum exergy efficiency of this combined system is 61.78% and the minimum cost of electricity production is 0.2617 $/kWh. In this regard, the multiple effect distillation system produces 530.9 KgS freshwater in 15 stages.

Evaluation of four different cogeneration cycles by using some criteria

Abstract The purpose of this article is to evaluate four different gas turbine cogeneration cycles which are basic, absorption cooling, air heating and air fuel heating cogeneration cycles by using the most important six evaluation criteria for different excess air coefficient, different compression rates, and different compressor inlet air temperatures. These six evaluation criteria are electrical heat ratio, exergy efficiency, incremental heat rate, artificial thermal efficiency, fuel energy saving ratio, and specific fuel consumption. It is seen that the air-fuel heating cogeneration cycle is the most efficient among the cycles examined for a certain compressor compression ratio, followed by the air heating, basic, and absorption cooling cycles.

Numerical investigation for optimization of spark-ignition internal combustion engine knock by Taguchi-Grey method.

This article carried out a numerical investigation of knock, using the Taguchi method and the grey relational analysis method to determine the importance and the contribution rate of multiple parameters on the peak pressure in the cylinder and the knock tendency under heavy load conditions. Four parameters, namely, compression ratio, spark timing, EGR rate, and inlet temperature, were set at four levels. The simulation was designed using a design of experiment method based on Taguchi's L16 orthogonal array. The simulation results of knock tendency and peak in-cylinder pressure were analyzed by the Taguchi-Grey method. According to the analysis results of the Taguchi-Grey method, the optimal level, the importance rank, and the contribution rate of factors on the knock tendency, peak in-cylinder pressure, and equivalent response were determined. The results demonstrate that the contribution rate of compression ratio, spark timing, EGR rate, and inlet temperature to the knock tendency is 45.9%, 22.98%, 19.46%, and 11.66%, respectively. The compression ratio, spark timing, EGR rate, and inlet temperature contribution to the peak in-cylinder pressure is 40.56%, 31.03%, 24.94 and 3.47%, respectively. The optimal conditions for the minimum knock tendency and the maximum peak in-cylinder pressure are obtained at CR1EGR4IT1ST1 and CR4EGR1IT1ST4, respectively.

Performance analysis and dynamic optimization of integrated cooling and power generation system based on supercritical CO2 cycle for turbine-based combined cycle engine

Turbine-based combined cycle (TBCC) engines are the most promising propulsion systems for the horizontal takeoff and landing of hypersonic vehicles. However, the high air-inlet temperature, engine-wall temperature, and electrical-energy demand hinder the application of the system. In this study, a novel integrated cooling and power generation system based on a supercritical CO2 recuperative Brayton cycle for hypersonic vehicles was proposed to meet the cooling requirements of each operating stage of a TBCC engine and to provide continuous power. Several optimization parameters able to balance the characteristics of the limited cold source, system weight, and power output of the system, such as the power-to-weight ratio and heat sink saving ratio, were proposed. With the help of optimization algorithms, the global performance curves and loads of each component were obtained during flights in the range of Mach 3.2∼6. The recuperator heat duty and compressor inlet temperature were key design parameters that affected system performance. The compressor inlet temperature is known to alter the heat sink utilization by changing the pinch point location in the gas cooler. The recuperator heat duty impacted both the system weight and power generation. The dynamic performance of the system indicated that the minimum heat sink saving ratio was approximately 10% during the entire flight, implying that the volume of fuel carried by the hypersonic vehicle could be reduced to some extent, while sufficient electricity was generated. The proposed system is a novel solution for thermal protection of TBCC engines and aircraft power generation technology under limited cold-source conditions.

Supercritical CO2 Power Cycle and Ejector Refrigeration Cycle for Marine Dual Fuel Engine Efficiency Enhancement by Utilizing Exhaust Gas and Charge Air Heat

Dual fuel engines with LNG as fuel have become a feasible solution for ship power units in the current situation, but their fuel efficiency needs to be further enhanced to meet the increasingly stringent emission requirements. This paper designs a dual-loop system, including a supercritical CO2 power cycle and a thermally driven ejector refrigeration cycle, for recovering the exhaust gas and charge air heat of a marine dual fuel engine. The models of the waste heat recovery system, the evaluation indicators of the combined system, and the genetic algorithm optimization program are developed. Compared to the standalone machine, the waste heat recovery system can improve by about 9.3% of the engine’s fuel efficiency. The performance analysis shows that the ejector contributes to the highest share of exergy destruction and accounts for approximate 53% of the refrigeration cycle. There are optimal values for the compressor inlet temperature of about 8.1 MPa and for the turbine inlet temperature of about 305 °C. Finally, after optimization, the specific fuel consumption, fuel efficiency, and CO2 emissions of the combined system are around 137.9 g/kWh, 53.3%, and 537.4 g/kWh, respectively. It provides a feasible solution in which the charge air cooler can be wholly replaced by the ejector refrigeration cycle.

Exergy Analysis of a Single-Shaft Gas Turbine Power Plant with Steam Injection

Exergy analysis has been performed on a single-shaft gas turbine with steam injection upstream (STIG) of the combustion chamber. The analysis will be performed to study the effect of increasing of compressor inlet temperature O1T design compressor pressure ratio cd PR and turbine inlet temperature O3T on the exergy destruction of STIG cycle components. For a specific value of steam mass flow rate: the increasing in O1T has a worthless effect on the exergy destruction of compressor and turbine while leads to increase in the exergy destruction of the combustion chamber. The increasing in cd PR leads to increase in the exergy destruction for all gas turbine power plant components. The increasing in O3 T leads to decrease in the exergy destruction of the combustion chamber, increase in the exergy destruction of the turbine, while has a worthless effect on the compressor. The biggest exergy destruction occurs in the combustion chamber For a specific values of O1T , cd PR , and O3 T steam injection will lead to improve the exergy destruction of the the combustion chamber, while has a reverse effect on the turbine, and has no effect on the compressor.