Variable Inlet Guide Vane Research Articles

Analysis of submersible axial flow pump fitted with variable IGV at design and off-design conditions

Abstract Submersible axial flow pump is capable of generating large flow rate at high efficiency and is widely used in agriculture, irrigation, water supply and drainage in factories, urban areas, etc. Pumps are always designed to operate at the designed conditions of flowrate and head, but in certain practical applications, their off- design operation seems to be more important, like if there is waterflooding due to heavy rainfall or in case of variable flowrate, variable head operations or long-distance water supply. These situations arise for limited operation (time) and hence it is not economical to change the existing pumping system. The present work deals with the analysis of submersible axial flow pump at design as well as off-design conditions. This off-design operation was controlled by the variable inlet guide vane (VIGV) with the task of making it energy efficient for all conditions. The scope of this work was to investigate the performance of selected pump at designed rotational speed, at designed flowrate (Q/Qd =1) as well as Q/Qd =0.8 and Q/Qd =1.2, using Computational Fluid Dynamics (CFD) and at various VIGV angles in the range of ±25°. The fluid flow analysis was performed using commercial CFD tool ANSYS CFX v17.0. From the numerical study, it was concluded that the performance of the considered AFP significantly increased due to the presence of VIGV at positive rotation angles. The best performance was observed for IGV angle of +25° for all flowrates. As compared to the reference case of 0° IGV rotation, the performance of the AFP increased by 28.42% in terms of head ratio and 0.235% in terms of hydraulic efficiency, for +25° IGV angle, at the designed flowrate. Also, an increment of 69.05% in terms of head ratio and 14.49% in terms of hydraulic efficiency was observed at overload condition of Q/Qd =1.2.

Mechanism of adjusting bypass ratio by front variable area bypass injector for a variable cycle engine

The Front Variable Area Bypass Injector (FVABI) is a key to bypass ratio adjustment for a Variable Cycle Engine (VCE). In order to study the role of the FVABI with the Core Driven Fan Stage (CDFS) duct, firstly, the engine bypass with the CDFS duct model and the equivalent engine bypass without the CDFS duct model are designed using the concept of a jet boundary line. By comparing the difference between airflow driving forces in the two engine bypass models, the quantitative effects of the injection from the CDFS duct on the mass flow rate of the engine bypass airflow are obtained under different combinations of pressure difference and area ratios. Then, the CDFS duct injection characteristic map is obtained through the typical experiment of the FVABI. Based on this map, the performance model of the FVABI is developed. Finally, the turbofan engine model with the Variable Inlet Guide Vane (VIGV), the First Variable Cycle Engine model (VCE1) with the CDFS duct and without the VIGV, and the Second Variable Cycle Engine model (VCE2) with the CDFS duct and VIGV are built. The gain on the engine bypass ratio adjustment range caused by the injection from the CDFS duct is clarified by comparing the three engine models. It is concluded that the bypass ratio adjustment range of the variable cycle engine with the FVABI is about twice that of the traditional turbofan engine.

Improving part-load performance of combined-cycle gas turbines by optimizing variable geometry control strategy for compressor and power turbine combined adjustment

The variable geometry methods currently used in combined-cycle gas turbines are compressor variable inlet guide vanes (VIGV) or power turbine variable area nozzles (VAN). On this basis, this study presents the optimal variable geometry control strategy for compressor and power turbine combined adjustment ([Formula: see text]) using the Differential Evolutionary Algorithm with the LM2500+ gas turbine. The aim is to further improve the part-load performance of the combined-cycle gas turbine. Firstly, a part-load performance prediction model for variable geometry gas turbines is established based on the component method. Subsequently, a variable geometry gas turbine part-load performance optimization model is developed by combining the Differential Evolution Algorithm. Finally, the optimum combination of stagger angles for the compressor inlet vane and power turbine nozzle is calculated at each part-load condition. Compared to the VIGV and VAN control strategies, the [Formula: see text] control strategy proposed in this paper shows a higher stability margin and better economy. The [Formula: see text] control strategy maintains a constant exhaust temperature within a part load range from 20% to 100% with the stability margin exceeding 14%. In comparison with the VAN control strategy, the fuel flow rate decreases by 1.152% at 45% relative load power and by 3.435% at 20.0% relative load power with the [Formula: see text] control strategy.

Study on the influence of variable inlet guide vane slot on the aerodynamic performance in air storage centrifugal compressor

The influence of variable inlet guide vanes with slots (SVIGVs) on the aerodynamic performance of an air-storage centrifugal compressor was studied using numerical simulations. The inlet position of the slot was set to 4 % of the chord length of the variable inlet guide vanes (VIGVs), and the outlet position was set to 14 %. The results show that the high-loss area near the VIGVs suction surface increases owing to the secondary flow generated by the slot jet, and the change in the inlet flow angle of the impeller results in a decrease in the compressor efficiency under the 30° pre-swirling angle condition. In contrast, the slot can effectively reduce the loss caused by the VIGVs at 40° and 50° pre-swirling angles and optimise the impeller inlet flow angle, thereby improving the efficiency and pressure ratio of the centrifugal compressor. At a pre-swirling angle of 50°, the efficiency and pressure ratio of the compressor increased by 8.3 % and 0.2, respectively. Furthermore, the influence of the SVIGVs on the impeller aerodynamic loads of a centrifugal compressor was revealed through an unsteady numerical simulation. The results showed that the SVIGVs effectively improved the aerodynamic load distribution on the impeller, reduced the aerodynamic load by three, four, and five times the frequency of rotation, and reduced the frequency amplitude by up to 2/3.

Innovative desalination system driven by a solar micro gas turbine for off-grid applications

Past work by the authors has suggested that Solar micro Gas Turbines (SmGTs) can be used cost-effectively to produce electric power and heat for freshwater production through desalination, mainly in off-grid locations. This is further studied in this work, providing an exhaustive modelling procedure and methodology. Additionally, a comprehensive analysis of system performance under both design and part-load conditions is provided along with the complete set of characteristics of the components of the SmGT and the desalination unit. To this end, the SmGT is assessed first, incorporating innovative solutions that enable better off-design performance: Variable Inlet Guide Vanes (VIGVs) in the compressor and Variable Nozzle Guide Vanes (VNGVs) in the turbine. The implementation of these features brings significant advantages in part-load operation, leading to a considerable increase in solar-to-electric efficiency and rangeability, particularly under certain ambient conditions; in particular, using these features yields 5% higher efficiency at the minimum load of the original engine (without variable geometry) and, from this load setting downwards, 15% lower minimum stable load is enabled. Furthermore, a sensitivity analysis to control strategies and ambient conditions has been included, exploring their impact on system performance.The water treatment system is comprised of two elements. A Reverse Osmosis (RO) desalination unit is driven by the electric power produced by the SmGT. Considering the emphasis on flexibility and part-load operation enhancement addressed in this work, a moderate recovery rate is proposed for this unit. The RO unit produces brine with high salt concentration to be partially treated further in a Zero Liquid Discharge (ZLD) unit driven by the exhaust gases of the microturbine (at about 250–300 °C), where the sensible heat of this stream is harvested by the ZLD unit to “dry” and concentrate the effluent. Finally, the potential and the operational limitations of the ZLD system are discussed, complemented with results from an experimental proof of concept where the feasibility of the concept is verified.

Synergistic Effect of Physical Faults and Variable Inlet Guide Vane Drift on Gas Turbine Engine

This study presents a comprehensive analysis of the impact of variable inlet guide vanes and physical faults on the performance of a three-shaft gas turbine engine operating at full load. By utilizing the input data provided by the engine manufacturer, the performance models for both the design point and off-design scenarios have been developed. To ensure the accuracy of our models, validation was conducted using the manufacturer’s data. Once the models were successfully validated, various degradation conditions, such as variable inlet guide vane drift, fouling, and erosion, were simulated. Three scenarios that cause gas turbine degradation have been considered and simulated: First, how would the variable inlet guide vane drift affect the gas turbine performance? Second, how would the combined effect of fouling and variable inlet guide vane drift cause the degradation of the engine performance? Third, how would the combined effect of erosion and variable inlet guide vane drift cause the degradation of the engine performance? The results revealed that up-VIGV drift, which is combined fouling and erosion, shows a small deviation because of offsetting the isentropic efficiency drop caused by fouling and erosion. It is clearly observed that fouling affects more upstream components, whereas erosion affects more downstream components. Furthermore, the deviation of performance and output parameters due to the combined faults has been discussed.

Investigation of off-design performance of supercritical carbon dioxide recompression cycle using a deep learning-based turbine with variable inlet guide vanes

Many control strategies have been proposed to improve the off-design performance of supercritical carbon dioxide (sCO2) cycles caused by changes in cycle parameters. However, the component-level control scheme solely utilizes the compressor with variable inlet guide vanes (VIGV) and not the VIGV-equipped turbine for the sCO2 cycle. In this study, we examine the potential of using a VIGV-equipped turbine in a supercritical carbon dioxide recompression cycle (sCO2-RC) heated by molten salt to enhance the system's off-design thermal efficiency under low-load conditions. To accurately model the system's behavior, one-dimensional design and off-design models of the sCO2-RC are developed, as simplified component models are inadequate. Following the completion of the preliminary design, we present the optimal off-design performance of the inventory-controlled system as the load changes. We then analyse the impact of the VIGV-equipped turbine on the system's performance at low load. The results show that when the load is decreased from 100% to 10%, both the system and turbine efficiencies decrease from 41.55% and 90% to 24.31% and 66.62%, respectively, and the surge margin of the compressor is significantly reduced. While the VIGV-equipped turbine improves the efficiencies of both the system and turbine at 10% load, the nozzle opening is constrained by the surge margin of the compressor. We propose a hybrid control strategy, comprising of inventory and turbine bypass, to facilitate the utilization of the VIGV-equipped turbine and enhance its efficiency while maintaining the system's performance no lower than the initial value.

Impact of Slots on the Aerodynamic Performance of the Variable Inlet Guide Vane Cascade of a Centrifugal Compressor

This study reconstructed the flow field of a symmetrical variable inlet guide vane in a centrifugal compressor through the passive control method of vane slots. Based on the high-fidelity numerical simulation model verified by experiments, the influence of different slot forms on the flow field was investigated, and the passive control mechanism was revealed. The results demonstrated that the vane slot method can effectively suppress the suction surface separation and broaden the range of low-loss incidence angles. Overall, the 50_30 slotted vane achieves the best flow field control, with a 65.6% reduction in the total pressure loss coefficient and a 2.3° reduction in the deviation angle, respectively, at a 25° incidence angle. The linear characteristics of the pre-swirl grade variation curve with variable inlet guide vane incidence angles are also improved. Furthermore, changing the slot outlet angle has the most significant influence on the aerodynamic performance as it changes the throat width of the location, thereby affecting the flow rate and momentum of the jet. Finally, the impact of the velocity varies in the first self-similarity region on the slotted vane. The results indicate that, in contrast to the baseline vane, the suppression effect of the slot jet on the flow separation improves with the inlet velocity, whereas the deviation angle of the slotted vane declines with the inlet velocity. Meanwhile, the higher the incoming flow velocity, the better the slotted jet can inhibition of flow separation.

Entropy production analysis of a radial inflow turbine with variable inlet guide vane for ORC application

The fluctuation of heat source conditions leads to the off-design operation and efficiency reduction of the radial inflow turbine (RIT). The adjustment of the outlet angle of inlet guide vane (IGV) is an important way to improve the turbine performance under off-design conditions. Since the energy dissipation caused by friction and flow separation is the main reason for the reduction of RIT efficiency, the entropy production analysis method is used to diagnose the location with high local energy loss in the RIT and evaluate its total energy loss under different working conditions in this paper. Firstly, an appropriate outlet angle of the IGV is determined according to the inlet pressure and outlet pressure of the RIT in organic Rankine cycle (ORC). Then, the effects of inlet pressure and outlet pressure on its energy loss are studied. The results indicate that the average entropy production rate (EPR) of the rotor in the RIT is the highest, which is mainly from the tip clearance and the inlet region. More than 70% of total entropy production of the turbine comes from the rotor, followed by the diffuser. The turbine can achieve lower total entropy production at higher outlet pressure or lower inlet pressure. Compared with a fixed IGV, the turbine with variable IGV can achieve higher turbine efficiency and output power under off-design conditions. The maximum increase in the efficiency and output power of the turbine with variable IGV under different inlet pressures is 3.8% and 12.9%, respectively.

Design Optimization and Variable Geometries Implementation of a High Bypass Three-Shaft Turbofan Engine for EIS2050

Abstract This paper aims to develop an advanced three-shaft turbofan engine with ultrahigh bypass ratio (BPR) for entry-into-service (EIS)2050. The boundary approaching method is utilized to obtain the optimal engine for a series of engines with different fan diameters. Furthermore, the flight mission analysis was carried out to fully consider the engine performance and weight penalty. The optimum engine employs a 3.26 m fan diameter with ultrahigh BPR reaching 21.39. The corresponding specific fuel consumption (SFC) is 11.42 (g/s)/kN, which is 3.88% lower than the 2.95 m fan diameter engine. However, the weight penalty has offset part of the benefits, and the block fuel reduction is 2.5%. Sensitivity analysis results reveal that the low-pressure turbine (LPT) efficiency plays a dominant role in engine performance. Afterwards, the effects of variable geometry are investigated including the blow-off valve (BOV), variable inlet guide vane (VIGV), and bypass variable area nozzle (VAN). Results show that combining the three measures would boost engine performance and save fuel. The designed schedule for the combination of VIGV, BOV, and VAN has generated a reduction in block fuel, NOx, CO2, and H2O reaching 3.36%, 5.55%, 2.47%, and 2.53%, respectively.

A New Test Facility for Advanced Testing of Variable Inlet Guide Vanes

Various experimental and numerical studies of advanced blade configurations for variable inlet guide vanes (VIGVs) were conducted during the past years. Nevertheless, experimental loss characteri-zations of VIGV blade designs vastly focused on the primary profile losses. Secondary flow losses as they occur in a real engine application were often neglected. For this reason, a new wind tunnel facility was erected and commissioned at the Bundeswehr University Munich to enable extensive investigations of application-oriented annular VIGV configurations at typical low subsonic Mach numbers. Five-hole probe field traverses are established by a probe traversing unit in the in-and outflow region of the VIGV. The requirements for a further extension of the applicable measuring techniques by optical methods is moreover provided. Thus, not only profile losses caused by the blades, but also secondary flow losses generated by blade-wall flow interactions and the open blade tips can be resolved in detail.

Numerical Investigation of Transient Flow Characteristics in a Centrifugal Compressor Stage with Variable Inlet Guide Vanes at Low Mass Flow Rates

This study numerically investigates the beneficial effects of positive pre-swirl on the aerodynamic performance and internal flow field in a centrifugal compressor stage with variable inlet guide vanes (VIGVs) at low mass flow rates. Four positions of VIGV are considered, including 0°, 30°, 45°, and 60° angle. The latter three positions of VIGV induce positive pre-swirl. Numerical results show that as positive pre-swirl increases, the aerodynamic performance curve of the stage moves in the low mass flow rate direction. In the three cases of positive pre-swirl, there was an improvement of approximately 9.95% of stall/surge margin greater than in conditions with no pre-swirl. The regulation of IGV can effectively improve the unstable flow of the compressor stage at low mass flow rates. A low frequency that has a great influence on the internal flow of the compressor stage is found, and the unstable flow caused by low frequency is analyzed by the combination of streamline distribution, spectrum analysis, vector, entropy increase, and modal decomposition method. Meanwhile, the modal decomposition method and flow field reconstruction techniques are used to investigate the coherent flow structures caused by low frequency under different guide vane openings.

Optimal detailed design and performance assessment of natural gas pressure reduction stations system equipped with variable inlet guide vane radial turbo-expander for energy recovery

The turbo-expander system is utilized instead of the pressure regulator to avoid exergy destruction occurring in gas pressure reduction systems. However, due to the variation of natural gas input conditions such as mass flow rate, the sustainable performance of this technology is challenging. In this study, at first, the optimal system design of gas pressure reducing station equipped with radial expansion turbine is performed. It is based on economic and exergy analyses as well as considering geometric, fluid, thermodynamic constraints of components and the systematic constraints. To do so, detailed design models of main components including mean-line design model of radial turbine, mathematical model of heat exchanger and design model of fired heater are developed. Then, the annual proficiency of the optimal system in dynamic conditions was evaluated according to the strategies considered for having stable production. One of the solutions is to improve the turbine efficiency by adjusting the angle of nozzle blades regarding the changes in mass flow rate. Therefore, our developed mean-line off design model of the turbine is applied to adjust inlet guide vane angle in the off-design situation to improve continuous electricity generation. The results of the design section show that the exergy efficiency on this occasion can achieve up to a maximum of 40%. Compared with fix inlet guide vane (IGV), applying variable IGV improves efficiency of turbine up to 60% at off-design condition. The Levelized cost of electricity (LCOE) and payback period of selected optimal design are about 0.0236 $/kWh, and 4 years, respectively. It indicates that this technology could be the economic option compared to other power generation systems.

Loss Characterization of a Conventional Variable Inlet Guide Vane

Variable inlet guide vanes (VIGVs) are most commonly used as the major control unit of integrally geared centrifugal compressors (IGCCs). In order to enhance the efficient operating range of the compressor, the loss mechanisms and utilization limits of state-of-the-art VIGVs need to be better understood. Field measurements in the wake of a typical, commercially used configuration were therefore conducted at the VIGV test facility of the Bundeswehr University Munich. The investigations were carried out at application oriented subsonic flow conditions and stagger angles from 50∘ to 90∘ covering the full low-loss operating range, including the limits of efficient operation. For a precise local loss characterization, an inflow correlation was developed and applied to consider total pressure inhomogeneities caused by the radial inflow velocity profile and minor circumferential velocity deviations. Contrary to previous research efforts, not only the profile losses, but also the secondary flow losses induced by the open blade tips and wall-blade interactions were resolved in full detail. For this reason, a more precise and comprehensive loss assessment of realistic VIGV cascades is acquired.

Effects of number of inlet guide vanes on the aerodynamic performance of a centrifugal compressor

Variable inlet guide vanes (VIGVs) are widely used for flow throttling and also extending the operating range of centrifugal compressors. Although there are several studies on the effects of adding IGVs on the performance curve of the compressors, none of them have focused on the number of vanes. In the current study, high-fidelity three-dimensional numerical simulations are carried out to analyze the effects of adding VIGVs with different number of vanes on the aerodynamic performance of a single-stage centrifugal compressor. The selected compressor prototype is a high flowrate single-stage compressor equipped with a vaned diffuser, designed and fabricated by Siemens. Computational fluid dynamic simulations are performed for three different number of guide vanes at three IGV inclination angles of 0, −30 and +45 degrees. The numerical results are validated by comparing the pressure-rise curves with the available experimental data of the compressor data sheet, where a good agreement was achieved. Results show that at the fully-open condition, the number of vanes does not have considerable effect on the performance curve of the compressor. However, as the IGV inclination angle increases, the number of inlet vanes plays a considerable role in the compressor efficiency. For example, at IGV inclination angle of +45 degree, increasing the number of vanes from 7 to 11 can increase the compressor maximum efficiency up to 5 points. Numerical results showed that increasing the number of inlet guide vanes imposes a higher pressure drop in the inlet passage of the compressor while generating a more uniform velocity distribution at the suction surface of the impeller. Due to the existence of several counteracting effects, an optimum number of inlet guide vanes can be found.

Effect of the Reynolds Number and Clearance Flow on the Aerodynamic Characteristics of a New Variable Inlet Guide Vane

Recently, a new type of low-loss variable inlet guide vane (VIGV) was proposed for improving a compressor’s performance under off-design conditions. To provide more information for applications, this work investigated the effect of the Reynolds number and clearance flow on the aerodynamic characteristics of this new type of VIGV. The performance and flow field of two representative airfoils with different chord Reynolds numbers were studied with the widely used commercial software ANSYS CFX after validation was completed. Calculations indicate that, with the decrease in the Reynolds number Rec, the airfoil loss coefficient ω and deviation δ first increase slightly and then entered a high growth rate in a low range of Rec. Afterwards, a detailed boundary-layer analysis was conducted to reveal the flow mechanism for the airfoil performance degradation with a low Reynolds number. For the design point, it is the appearance and extension of the separation region on the rear portion; for the maximum incidence point, it is the increase in the length and height of the separation region on the former portion. The three-dimensional VIGV research confirms the Reynolds number effect on airfoils. Furthermore, the clearance leakage flow forms a strong stream-wise vortex by injection into the mainflow, resulting in a high total-pressure loss and under-turning in the endwall region, which shows the potential benefits of seal treatment.

Simulation of Optimizing the Partial Load Performance of a Gas Turbine Combined Cycle Using Exhaust Heat Recuperation and Inlet Bleed Heating

Abstract This paper proposes a novel method to extend the operating range and improve the partial load efficiency of the gas turbine combined cycle (GTCC). The combination of exhaust heat recuperation and inlet bleed heating (IBH) was evaluated through a cycle simulation. The degree of heat recuperation was modulated during partial load operation to enhance the cycle efficiency. The recuperation ratio was modulated before control of the variable inlet guide vane (VIGV) began. This means that the recuperation control covers the high partial load regime. The gas turbine power remained almost constant in this regime because the inlet flow rate and turbine inlet temperature (TIT) were kept constant. In contrast, the power of the bottoming cycle decreased with increasing recuperation ratio due to the decrease in exhaust gas energy. After the recuperation ratio reached a limit, the load control was the same, as in conventional plants: VIGV control followed by fuel only control. The purpose of using IBH was to reduce CO emissions in the low load regime. Some of the compressor discharge air was recirculated to the compressor inlet, and the combustion temperature was maintained at a high level. Both IBH and recuperation were effective in extending the operating range. The turndown ratio was predicted to decrease by approximately 10%p. The efficiency remained higher than the full load efficiency over a wide partial load range. The efficiency of the recuperated GTCC was 4.1%p higher at 50% power than that of the conventional GTCC.

Performance Assessment of a Heat Recovery Unit Utilizing Turbine with Variable Inlet Guide Vanes Configuration for Application in Passenger Vehicles

This study explores the potentials of employing an Organic Rankine Cycle (ORC) system with variable inlet guide vanes (VIV) turbine geometry designed on a GT-Suite platform for effective exhaust heat recovery (EHR) application onboard passenger vehicles. The ORC model simulation was based on vehicle speed mode using R245fa as working fluid to assess the thermal performance of the ORC system when utilizing modified turbine geometry. Interestingly, the model achieved a very improved performance in contrast to the model without a modified turbine configuration. The results revealed the average 2.32 kW ORC net output, 4.93% thermal efficiency, 6.1% mechanical efficiency, and 5.0% improved brake specific fuel consumption (BSFC) for the developed model. As determined by the performance indicators, these promising results from the model study show the prospect of EHR technology application in the transportation sector for reduction in exhaust emissions and fuel savings.

Leading edge redesign of dual-peak type variable inlet guide vane and its effect on aerodynamic performance

Recently, a new type airfoil for variable inlet guide vane (VIGV), featuring “dual-peak” surface velocity pattern at high incidence, is proposed and shows wide low-loss operation range. To further improve its performance, this paper researches the influence of leading edge (LE) thickness and shape on the loss level and surface velocity features of the “dual-peak” type airfoil. Firstly, a polynomial-based continuous-curvature leading edge design method was briefly introduced and used in the LE redesign of sample airfoils. Then, steady simulations based on Reynolds-Averaged Navier-Stokes method (RANS), carried out by commercial software CFX after grid independent study, were used to determine the aerodynamic performance, surface velocity distribution and boundary-layer behaviors of all research airfoils. Simulation results indicate that there exists an optimized range of LE relative thickness that can achieve lower airfoil loss level at high incidence condition. For Case 1 ([Formula: see text]) and Case 2 ([Formula: see text]), the optimized LE relative thickness range is [Formula: see text] and [Formula: see text]. The LE shape optimization can further reduce the maximum incidence condition loss coefficient with proportion up to 18% for airfoils with optimal LE thickness. Analysis of flow mechanism indicates that the optimized LE thickness and shape can reduce the suction spike height and subsequent adverse pressure gradient, therefore, decrease the LE separation scale and result in a lower loss coefficient. As an application, a dual peak VIGV with circular LE, presented in previous paper as the optimized VIGV, is redesigned in the LE portion according to the research findings and achieved 0.6 percent improvement in passage-averaged total pressure recovery coefficient [Formula: see text] at extreme high stagger angle point and the low-loss operation range extends with about 5°, which confirms the effectiveness of the research findings in three-dimensional environment.

Aerodynamic and Aeroelastic Effects of Design-Based Geometry Variations on a Low-Pressure Compressor

In modern aircraft engines, the low-pressure compressor (LPC) is subjected to a flow characterized by strong wakes and secondary flows from the upstream fan. This concerns ultra-high bypass ratio (UHBR) turbofan engines, in particular. This paper presents the aerodynamic and aeroelastic sensitivities of parametric variations on the LPC, driven by the design considerations in the upstream fan. The goal of this investigation was to determine the influence of design-based geometry parameter variations on the LPC performance under realistic inlet flow distributions and the presence of an s-duct. Aerodynamic simulations are conducted at the design and off-design operating points with the fan outflow as the inlet boundary conditions. Based on the aerodynamic results, time-linearized unsteady simulations are conducted to evaluate the vibration amplitude at the resonance operating points. First, the bypass ratio is varied by reducing the channel height of the LPC. The LPC efficiency decreases by up to 1.7% due to the increase in blockage of the core flow. The forced response amplitude of the rotor decreases with increasing bypass ratio due to increased aerodynamic damping. Secondly, the fan cavity leakage flow is considered as it directly affects the near hub fan flow and thus the inflow of the LPC. This results in an increased total-pressure loss for the s-duct due to mixing losses. The additional mixing redistributes the flow at the s-duct exit leading to a total-pressure loss reduction of 4.3% in the first rotor at design point. This effect is altered at off-design conditions. The vibration amplitude at low speed resonance points is increased by 19% for the first torsion and 26% for second bending. Thirdly, sweep and lean are applied to the inlet guide vane (IGV) upstream of the LPC. Despite the s-duct and the variable inlet guide vane (VIGV) affecting the flow, the three-dimensional blade design achieves aerodynamic and aeroelastic improvements of rotor 1 at off-design. The total-pressure loss reduces by up to 18% and the resonance amplitude more than 10%. Only negligible improvements for rotor 1 are present at the design point. In a fourth step, the influence of axial gap size between the stator and the rotor rows in the LPC is examined in the range of small variations which shows no distinct aerodynamic and aeroelastic sensitivities. This finding not only supports previous studies, but it also suggests a correlation between mode shapes and locally increased excitaion with increasing axial gap size. As a result, potential design improvements in future fan-compressor design are suggested.