Distortion Coefficients Research Articles

Harmonic distortion calibrator: additional uncertainty due to distortion in the measurement cable

The role of measuring instruments of the reference level (working standards of the 1st and 2nd digits) in ensuring the uniformity of measurements of the harmonic coefficient is considered, namely, the transfer of a unit of the harmonic coefficient from the primary standard to all measuring instruments from a huge fleet of working measuring instruments. A continuous search for ways to reduce the error of these measuring instruments is required. The methods of reducing one of the components of the measurement error of the reference level – an additional error caused by distortions in the measuring cable due to a mismatch of the resistances at the output of the calibrator and the input of the meter – are investigated. Until recently, the influence of measuring cable parameters on the results of harmonic coefficient measurements was considered negligible, because harmonic coefficient measuring instruments operate at sufficiently low frequencies (less than 1 MHz). However, for modern reference-level measuring instruments, such an influence has become noticeable, and it needs to be investigated. It has been shown that for calibrators with a large (600 Ohm) output impedance, significantly exceeding the characteristic impedance of the measuring cable, this error can be significant. An analytical dependence of the indicated error on the parameters of the measuring cable and the calibrator signal, as well as the output resistance of the calibrator, is derived. Conditions have been established under which this additional error is absent or can be neglected due to its smallness. When checking harmonic coefficient measuring instruments, a measuring cable 1 m long with a characteristic impedance of 50 Ohms is most often used. For a cable with such parameters and different values of the output resistance of the calibrator, the indicated additional error was theoretically calculated and experimentally evaluated. For a signal with a fundamental frequency of 200 kHz and a uniformly decreasing distribution of harmonic levels with a calibrator output impedance of 600 Ohms, the additional absolute error in generating a harmonic distortion equal to 100 % is 3 %. The use of factory correction for the total error in the formation of the harmonic distortion coefficient of the manufactured calibrator allows us to reduce the additional error only partially. To significantly minimize the additional error of the calibrator used, it is necessary to use the measuring cable supplied with the calibrator or a cable with identical parameters. The experimental estimate of the additional error is in good agreement with the results of its calculations. It is recommended to take into account the additional absolute error in the formation of the harmonic coefficient when developing and testing instruments for measuring the harmonic coefficient.

Obstacles to the development of China's marine economy: Total factor productivity loss from resource mismatch

The total factor productivity (TFP) of the marine economy loss due to the resource mismatch remains a major obstacle to the development of China's marine economy. This study analyzes the intrinsic mechanism of the four types of capital mismatches, including natural, knowledge, social, and institutional, affecting the TFP of the marine economy. Firstly, the Stochastic Frontier Analysis model is used to obtain the TFP in 11 Chinese coastal provinces from 2000 to 2020. Then the four types of capital are unified into the HK model to study their spatio-temporal characteristics, and the extended Syrquin decomposition is used to analyze the sources of the changes in the marine economic output during the whole study period. At the same time, we estimate the output gap and the contribution of distortionary changes in each type of resource. Finally, we use Bootstrap to measure the impact of each type of resource mismatch on TFP. The results show that ① TFP is on the rise and belongs to the middle level. Nevertheless, there is a slow growth rate, noticeable regional differences, with a specific "path dependence". ② All capitals are distorted, and only the distortion coefficient of natural capital is greater than 1. Spatially, resources are under-allocated in the economic pioneer regions and over-allocated in the latecomer regions. ③ At present, China's marine economic growth is mainly driven by resource inputs. Correcting the inter-regional resource distortion can raise output by 21%. ④ The contribution of knowledge and social capital distortions is positive but small, while institutional and natural capital contribute more but fluctuate sharply. Resource allocation tends to be rationalized in Shanghai, Zhejiang, Fujian, Shandong, and Guangdong. ⑤ The mismatch of natural capital shows an “inverted U-shaped” trend, with 2006 as the "inflection point". The mismatch of knowledge, social, and institutional capital shows a decreasing trend and remains stable. Mismatch of all capitals harms the TFP of the marine economy, and institutional capital mismatch has the greatest impact. This assessment framework can measure the extent of other resource mismatches in other regions of the world, and the results of the study can provide lessons for localities to promote efficient resource allocation and enhance TFP in the marine economy.

Analysis of Reactive Power in Electrical Networks Supplying Nonlinear Fast-Varying Loads

This study concerns problems related to the assessment of reactive power in power networks with nonlinear fast-varying loads, such as electric arc furnaces, rolling mill drives, etc. The operation of this type of load is characterized by the introduction of interharmonic currents (including higher harmonics) into the power supply network and a relatively low power factor. Rapid changes in the RMS value of the current also cause voltage fluctuations and the related phenomenon of light-flickering. Therefore, there is a need to evaluate the power selection of compensating devices, taking into account the random nature of load changes and the distortion of current and voltage waveforms, in particular, interharmonic components, the impact of which has not been fully investigated so far. To analyze the random nature of load changes, autocorrelation functions were used, which allowed for the estimation of the expected values of the arc furnace current distortion coefficient (based on the recorded waveforms). In order to determine the parameters of reactive power compensating devices, and in particular capacitor banks, an autocorrelation function in the exponential-cosine-sine form was used, which meets the conditions of differentiation. This study contains comparative results of the reactive power of capacitor banks determined using different methods. The criterion for selecting capacitor bank parameters was the minimization of energy losses in the power supply network. The calculations presented in this study show that by taking into account higher harmonics and interharmonics in the voltage and currents of fast-varying loads, the installed power of the capacitor bank can be reduced by approximately 7%, and energy losses in the power grid can be reduced by 3–5%.

A novel distance measure based on dynamic time warping to improve time series classification

Dynamic time warping (DTW) is the most widely used method to evaluate the similarity between time series. However, the DTW distance only takes into account the difference in amplitude, but does not reflect the time distortion information between them. In this paper, we propose a novel time similarity metric, called the time distortion coefficient, based on the DTW warping path to quantify the time distortion between time series. It is able to characterize the type and degree of time distortion between two time series at each point. By summing the absolute values of the time distortion coefficients, the overall time distortion is introduced to quantify time distortion between two time series. For the Nearest Neighbor (NN) based time series classification, a fusional similarity measure combining the DTW distance and the overall time distortion measure is proposed, which is able to evaluate the similarity in both amplitude and time domains. The experimental results conducted on the UCR time series classification archive datasets demonstrate that the proposed fusional similarity measure can significantly improve the classification accuracy of the 1-NN classifier with only a small amount of additional computational cost compared to the DTW distance and other metrics.

Effect of Urban Household Registration Controls on Labor Mismatch in China

This study examines the effect of the degree of household registration control on labor mismatch in China. Based on Chinese urban panel data, we construct a dynamic panel model to empirically examine the effect of the degree of household registration control on labor mismatch in China. The study finds that labor mismatch relatively exists in all regions of China, which differ significantly. Moreover, liberalizing the household registration system in cities with under- and over-allocated labor force can reduce and aggravate the degree of local labor mismatch, and improve and reduce resource allocation efficiency, respectively. This study uses the labor distortion coefficient to replace the original dependent variable, and the labor mismatch coefficient. The authors further conduct a robustness test using the system generalized moment estimation method. These results are consistent. The implication of this study is that, in the context of China’s shift from high-speed to high-quality development, local governments should tailor their household registration system reform programs to the local resource allocation situation to improve the degree of labor mismatch in China, to optimize resource allocation, and to promote economic transformation.

Propriétés remarquables de la réfraction astronomique dans une atmosphère à symétrie sphérique

The general theoretical properties and various approximate formulas for the angle χ S of astronomical refraction at S are presented, beginning with its fundamental expression by the refraction integral and immediately leading to the Simpson formula. Assuming a spherically symmetric atmosphere, many additional results show up, starting with Oriani’s “theorem” and Bouguer’s equation. From these, an usual form of the refraction integral is derived. A fundamental approximation follows to deduce the Laplace formula, then the series expansions that generalize it but are divergent for an isothermal atmosphere—because of the approximation made. Two results, free from any approximation, exist and are presented: Biot’s and Biot–Sang–Meyer–Fraser–White’s theorems. It leads to an approximate link with extinction, as found by Laplace, and an approximation of the refraction χ Sh for points on the astronomical horizon. We compute the chromatic effects on χ S , χ Sh —and (in a document associated with this article) on various characteristics of optical ducts considered in air—and an original expression of the “local vertical angular distortion coefficient” on the horizon (in Annexe B).

Characteristic analysis of a controlled-clearance piston-cylinder assembly up to 1500 MPa using a finite element method

We utilized numerical methods to analyze the characteristics of the piston-cylinder assembly of a controlled-clearance piston gauge. The piston gauge was able to measure liquid pressure from 100 MPa to 1500 MPa with the relative expanded uncertainty of 0.02% (k = 3). We established a finite element model to solve the stress and strain of the structural problem. The effective areas were calculated based on Dadson’s formula using the converged solutions of the clearance and the pressure distribution within the distorted piston-cylinder engagement gap that were iteratively determined by the finite element model and a fluid mechanics model with pressure-dependent fluid’s properties. Results were compared to the effective areas calculated by the modified Heydemann–Welch model based on experimental data, and the relative differences were less than 0.02%. We found sharp declines of the clearance and pressure distribution near the exit of the piston-cylinder engagement gap, which may lead to wearing during long-time operation at high pressures. Numerical results indicated non-linear relationship between jacket pressure and the cubic root of piston fall speed, which was traditionally considered as linear. The stall jacket pressure obtained by cubic (instead of linear) fitting extrapolation was found more close to the ones determined directly by the finite element model. Numerical results also found non-linear relationships among jacket pressure, measuring pressure, jacket pressure distortion coefficient.

Numerical Investigation into Characteristics of WIPCC and Distortion of S-shaped Intake

Water injection pre-compressor cooling technology can efficiently increase the engine thrust and expand the flight envelope of the aircraft. Changes in the curvature of the intake and the evaporative cooling of the spray medium naturally distort the total pressure, total temperature, and characteristics of the swirl of the flow before it enters the engine. This study conducts numerical research on the aerothermal process of the WIPCC in an S-shaped intake using the Eulerian-Lagrangian method. The spatial evolution of critical variables along the flow direction and specific cross-sections were obtained by analyzing the statistical time-averaged results of multiphase flow. The transient distortion descriptors were quantified and analyzed following the SAE standard, which revealed the characteristics of various distortions and their spatial-temporal changes. Furthermore, the variables reflecting the transient flow structure were decomposed using the POD method to obtain the coherent structure of each mode and its frequency and energy characteristics. The results showed that aerodynamic breakup was the main cause of droplet size reduction and led to a decrease of 74.4% and 63.8% in Sauter droplet size under two conditions, respectively. The downstream mixing of flows in the S-duct mitigated the distortions caused by the intake's changing curvature and droplet evaporation. After the mixing of flows under specific conditions, the total pressure distortion coefficient decreased from 0.30 to 0.12, the swirl intensity decreased from 4°-6° to 2°-4°, and the high total temperature extent decreased from 0.65 to 0.35. The POD mode of the variables exhibited broadband characteristics with multiple spikes and energy dispersion. The main modes of the drop coefficients in total pressure and temperature corresponded to large- and small-scale structures, respectively, with Strouhal number ranges of 0.079-0.394 and 0.362-1.260. These results reveal the effects of WIPCC on the aerothermal processes in the S-shaped intake and the mechanism of generation and evolution of distortions. Moreover, the results provide reasonable boundary conditions for numerical investigations of wet compression under intake distortions.

Effects of Synthetic Jets on Swirl Inflow in a Variable-Geometry Twin Air-Intake

Air intakes are an integral part of contemporary passenger and military aircraft engines. Their impact on aerodynamic performance across the entire flight envelope is critical to aircraft flight safety, efficiency, and manoeuvrability, especially at high Mach numbers due to shock waves. The high demand for reductions in aircraft weight and size and enhancements in durability, comfort, and thermal and radar signatures compel researchers and engineers to explore new designs and develop efficient air intakes for high-performance aircraft engines. Although a number of studies on air intake have been conducted and reported in the open literature, there is little information available in the public domain on bifurcated twin air intakes using synthetic jet. As a result, the primary goal of this research is to use computational fluid dynamics modelling to investigate the effects of synthetic jets on swirl inflow variable geometry twin air intake aerodynamic performance over a range of Reynolds numbers. Some important parameters (distortion coefficient, non-uniformity index, swirl coefficient, and static and total pressure coefficients) were investigated. Both static and total pressure recovery have been increased at all swirl numbers. A significant decrease in distortion coefficient and swirl coefficient has also been achieved, reaching a 53% reduction in the distortion coefficient and a 62% reduction in the swirl coefficient. The reduction in the non-uniformity index is achieved by 62% for the controlled flow case. The findings show that synthetic jets are effective in controlling the flow separation in the twin air intakes and enhancing aerodynamic performance.

Automatic and Quantitative Measurement of Spectrometer Aberrations.

The performance of electron energy loss spectrometers can often be limited by their electron optical aberrations. Due to recent developments in high energy resolution and momentum-resolved electron energy loss spectroscopy (EELS), there is renewed interest in optimizing the performance of such spectrometers. For example, the "ω - q" mode of momentum-resolved EELS, which uses a small convergence angle and requires aligning diffraction spots with the slot aperture, presents a challenge in the realignments of the spectrometer required by the adjustment of the projection lenses. Automated and robust alignment can greatly benefit such a process. The first step toward this goal is automatic and quantitative measurement of spectrometer aberrations. We demonstrate the measurement of geometric aberrations and distortions in EELS within a monochromated scanning transmission electron microscope (STEM). To better understand the results, we present a wave mechanical simulation of the experiment. Using the measured aberration and distortion coefficients as inputs to the simulation, we find a good match between the simulation and experiment, verifying formulae used in the simulation. From verified simulations with known aberration coefficients, we can assess the accuracy of measurements. Understanding the errors and inaccuracies in the procedure can guide further progress in aberration measurement and correction for new spectrometer developments.

Observation of nonlinear disclination states

Introduction of controllable deformations into periodic materials that lead to disclinations in their structure opens novel routes for construction of higher-order topological insulators hosting topological states at disclinations. Appearance of these topological states is consistent with the bulk-disclination correspondence principle, and is due to the filling anomaly that results in fractional charges to the boundary unit cells. So far, topological disclination states were observed only in the linear regime, while the interplay between nonlinearity and topology in the systems with disclinations has been never studied experimentally. We report here on the experimental observation of the nonlinear photonic disclination states in waveguide arrays with pentagonal or heptagonal disclination cores inscribed in transparent optical medium using the fs-laser writing technique. The transition between nontopological and topological phases in such structures is controlled by the Kekulé distortion coefficient r with topological phase hosting simultaneously disclination states at the inner disclination core and spatially separated from them corner-I, corner-II, and extended edge states at the outer edge of the structure. We show that the robust nonlinear disclination states bifurcate from their linear counterparts and that location of their propagation constants in the gap and, hence, their spatial localization can be controlled by their power. Nonlinear disclination states can be efficiently excited by Gaussian input beams, but only if they are focused into the waveguides belonging to the disclination core, where such topological states reside. Our results open new prospects for investigation of nonlinear effects in topological systems with disclinations and are relevant for different areas of science, including Bose-Einstein and polariton condensates, where potentials with the disclinations can be created.

The Cross-coupling Problem of Helicopter Rotors - A Review

Until recently it was beyond the capability of helicopter rotor models to predict correctly the cross-coupling response. During the mid-nineties it became clear that wake distortion effects are the main contributors to the cross-coupling response. Wake distortion effects can be modeled by using detailed free or prescribed wake models. However, these models require large computer resources and long computing times, thus they are not suitable for various applications. In such cases dynamic-inflow models can be corrected to account for the missing effect, by using the wake distortion coefficient or an aerodynamic phase lag. Recently, a new actuator disk model was developed where the wake distortion effect is obtained as an integral part of the derivation. In the paper all the methods of considering the wake distortion effects are reviewed and compared. The results of the various models are also compared to flight test results. Conclusions are drawn and further necessary research is identified.

Visual measurement of the bearing diameter based on the homography matrix and partial area effect

A measurement method based on the homography matrix and partial area effect is studied to improve the precision of the visual measurement of the bearing size. Firstly, the camera is calibrated to obtain its distortion coefficient, and the image is corrected for distortion. Secondly, the relationship between the pixel plane and the bearing imaging plane is determined by solving the homography matrix with a chessboard. Finally, the sub-pixel edge contour of the bearing is obtained through the improved partial area effect, and the pixel coordinates are mapped to the world coordinates according to the homography matrix. The feature size is obtained by fitting the mapping points. Experimental results showed that the transformation of the homography matrix is more accurate than the pixel equivalent in the process of converting the pixel size to the actual size. The improved partial area effect sub-pixel edge detection results are better than the partial area effect and Zernike moment. The measurement error for the bearing outer diameter is less than 0.05 mm and is within 0.5 pixel.

Discounted Costs Range Criterion Modification for Controlled Asynchronous Electric Drives

A range criterion of discounted costs is proposed, which takes into account all costs for a speed-controlled asynchronous electric drive, including its price, costs of losses and maintenance, and amortization charges. It is also possible to take into account the cost and energy performance of matching transformers and gearboxes. Costs for reactive power compensation of both the first and second kind (due to the presence of harmonic components at the drive input) are taken into account. The latter requires determining the total harmonic distortion (THD) of the currents consumed by the drive. In the case of autonomous power systems, it is also necessary to determine the drive’s supplying voltage non-linear distortion coefficients. Representing the discounted costs as the sum of initial capital investments and annual costs made possible taking into account the presence of inflationary processes. The control characteristics of the active power consumed by the drive, efficiency, power factor, and phase shift factor are constructed, which are dependencies on the rotation frequency in a certain control range at a specific load. It is proposed to calculate the drive’s discounted costs criterion, depending on the operating mode of the load. According to the mode, the criterion is calculated as an average range in a certain range of speed control or is determined taking into account a given tachogram of speed changes. For the controlled asynchronous drive under consideration, the discounted costs are 4148 c.u. in the first case and 5139.3 c.u. in the second case. If inflationary processes are taken into account, the first case is 4219.4 c.u. and the second case is 5227.7 c.u., respectively.

An AC-DC LED Integrated Streetlight Driver with Power Factor Correction and Soft-Switching Functions

The use of light-emitting diodes (LEDs) in street lighting applications has been greatly welcomed with the current trends of energy saving, environmental protection, carbon reduction, and sustainable development. This paper presents a novel AC-DC LED integrated streetlight driver that combines an interleaved buck converter with a coupled inductor and a half-bridge series resonant converter with a full-bridge rectifier into a single-stage power conversion topology with power factor correction (PFC) and soft switching capabilities. The PFC is achieved by designing the coupling inductor in the interleaved buck converter sub-circuit in discontinuous conduction mode. In addition, the resonant tank in the half-bridge series resonant converter sub-circuit is designed to be similar to an inductive load, thus giving the power switch a zero-voltage switching (ZVS) function, decreasing switching losses and increasing the overall efficiency of the proposed circuit. A prototype circuit of the proposed LED integrated streetlight driver with a power rating of 165 W (235 V/0.7 A) and 110 V input utility voltage has been developed and tested. According to the measurement results, a power factor greater than 0.98, a total harmonic distortion coefficient of the input current less than 3%, and an efficiency greater than 89% were obtained in the AC-DC LED integrated streetlight driver. Therefore, the experimental results are satisfactory and demonstrate the functionality of the proposed AC-DC LED integrated streetlight driver.

Self-Consistent Positive Streamer-Leader Propagation Model Based on Finite Element Method (FEM) and Voltage Distortion Method (VDM)

Researchers have worked on positive leader propagation models and proposed different theoretical and numerical approaches. The charge simulation method (CSM) has traditionally been chosen to model the quasi-static electric field of each stage of leader propagation. The biggest drawback of the CSM is that the calculation is complicated and time-consuming when dealing with asymmetric electric field structures. On the contrary, the finite element method (FEM) is more suitable and reliable for solving electrostatic field problems with asymmetric and complex boundary conditions, avoiding the difficulties of virtual charge configuration and electric field calculation under complex boundary conditions. This paper modeled a self-consistent streamer-leader propagation model in an inverted rod-plane air gap based on FEM and the voltage distortion method (VDM). The voltage distortion coefficient was analyzed to calculate the streamer length and space charge. The physical dynamic process of the discharge was simulated with the help of COMSOL Multiphysics and MATLAB co-simulation technology. The results show that the initial voltage of the first corona is -1036 kV, close to the experiment value of -1052 kV. The breakdown voltage of -1369 kV is highly consistent with the experimental value of -1365 kV. The largest streamer length is 2.72 m, slightly higher than the experimental value of 2.3 m. The leader velocity is 2.43×104 m/s, close to the experiment value of 2.2×104 m/s. This model has simple calculations and can be used in complex electrode configurations and arbitrary boundary conditions without simplifying the model structure, making the model more flexible.

Calibration of central catadioptric cameras based on the projection properties between the right and oblique cones.

Central catadioptric cameras with a single effective viewpoint can easily transform the original image into a perspective image. In this study, we proposed a calibration algorithm for central catadioptric cameras. A vanishing line was recovered by the images of two sphere images (or line images) and mirror contour based on the properties of right and oblique cones. Subsequently, the intrinsic parameters were solved by the image of circular points and the orthogonal vanishing points. Finally, the distortion coefficient was estimated based on the geometric properties of the right cone. The simulation and real-time experiments conducted proved the effectiveness and feasibility of the proposed algorithm.

Numerical Investigation on the Effect of Height-to-Radius Ratio on Flow Separation Features in S-Shaped Diffuser with Boundary Layer Ingestion

The flow separation occurring in the S-shaped diffuser with boundary layer ingestion (BLI) has a significant effect on the performance of the embedded engine. Previous studies have found that the area ratio (AR) as well as the length-to-offset ratio (LOR) of the S-shaped diffuser are the key contributing factors that affect the flow separation features. Based on the flow phenomena observed in previous studies of an S-shaped diffuser with 100% BLI, a hypothesis that the parameter height-to-radius ratio (HRR) may also have significant effect on the flow separation features in the S-shaped diffuser is proposed. The purpose of this paper is to verify this hypothesis and to further investigate the effect of HRR on the flow separation features in the S-shaped diffuser with BLI using numerical methods. First, the hypothesis that HRR has an effect on the flow separation features in the S-shaped diffuser is verified under uniform inlet condition. Second, the effect of HRR on the flow separation features is investigated under different relative heights of inlet BLI. It is found that the flow separation features in the S-shaped diffuser are very sensitive to the change in HRR but not to the change in relative height of inlet BLI. Finally, for the fixed boundary layer height generated from the airframe, the S-shaped diffuser with a smaller design HRR can significantly suppress the flow separation and thus achieve a higher total pressure recovery and a lower distortion coefficient. The results provide improved understandings of the factor affecting the flow separation features in the S-shaped diffuser, and are useful for improving the aerodynamic performance of the embedded engine with BLI.

The heterogeneity impact of factor market distortions on GTFP: from the view of resource-based cities.

Improving the efficiency of factor allocation, breaking the resource curse, and achieving high-quality economic development are an urgent concern in resource-based cities. Using the panel data of 116 prefecture-level resource-based cities in China from 2005 to 2020, this paper constructs the data envelopment analysis-Malmquist index model to measure the level of high-quality economic development; to construct a resource misallocation growth accounting model based on the total production function to measure the distortion coefficient, the threshold panel model is employed to explore the threshold effect of factor market distortion on high-quality economic development. The results yielded three important findings: (1) The green total factor productivity of resource-based cities in China presents spatial heterogeneity and type heterogeneity. (2) Factor market distortion gradient standards are proposed innovatively, and the factor market distortion level shows the spatial heterogeneity and type heterogeneity. (3) The influence of factor market distortion on high-quality economic development in resource-based cities presents a double threshold effect. According to the above research conclusions, this paper gives several policy recommendations to promote the factor marketization allocation and high-quality economic development of resource-based cities.

Study on the Influence of Radial Inlet Chamber Splitter Blades on the Oblique Flow Compressor Performance

The oblique flow compressor is one of the important components in the compressed air energy storage (CAES) system. The structural shape of the radial inlet chamber (RIC) directly affects the compressor performance, and a reasonable RIC design should achieve the smallest total pressure loss and outlet distortion as much as possible to meet the structural design. To study the influence of splitter blades, 4 RICs equipped with different numbers of splitter blades are designed, and the performance of 4 RICs and the overall performance of the compressor is calculated. The results show that with the increase in the number of splitter blades, the stall margin increases from 6.3% to 13.94%. At the design point, the isentropic efficiency is highest for the RIC with 17 splitter blades, and the pressure ratio is highest for the RIC with 11 splitter blades. Compared with the direct axial intake mode, the uniformity of the relative leakage distribution and the attack angle distribution of the impeller leading edge under 4 radial intake modes are poor. However, with an increase in the number of splitter blades, the uniformity of the relative tip leakage and the attack angle distribution gradually increase. The flow loss of RIC will increase simultaneously, though the uniformity of the outlet aerodynamic parameters distribution improves, and the influence on the downstream component performance gradually weakens. There is an optimal number of splitter blades in RIC, which balances the total pressure loss and distortion coefficient.