Streaming Rate Research Articles

Numerical investigation on flow characteristics of multi-stream supersonic nozzle with serpentine configuration

The serpentine configuration is utilized in the multi-stream supersonic nozzle of the Adaptive Cycle Engine to improve the stealth performance of next-generation fighters. Compared to single-stream conventional nozzles, the multi-stream supersonic nozzle involves a larger number of design parameters and exhibits a strong interaction between the multiple streams. The serpentine configuration introduces a complex influence on the flow characteristics of the multi-stream supersonic nozzle, which presents significant challenges in designing high-performance nozzles. It is crucial to understand and effectively manage the flow features to optimize the design of multi-stream supersonic nozzles with a serpentine configuration. As a result, the effects of the serpentine configuration and nozzle pressure ratio (NPR) on the flow characteristics of the multi-stream supersonic nozzle were investigated numerically in this paper. The numerical simulation employs the implicit density-based algorithm and Shear Stress Transport k-ω turbulent model of the commercial software ANSYS Fluent. The results show that the shock waves and contra-rotating vortices are generated by the nonuniform main stream and corner vortices from the serpentine configuration when the streams mix, which lead to the decline of the aerodynamic performance compared to the no serpentine case. The mass flow rate of the main stream and tertiary stream reduce by 1.4 % and 4.2 %, respectively, and the thrust performance reduces by 0.35 %. As the NPR rises, the tertiary streams are compressed by the main stream. The mass flow rate of the tertiary streams drop sharply with the contraction of the actual throat area. The flow condition of the tertiary streams convert from the over-expanded condition of convergent-divergent nozzle to the critical condition of convergent nozzle. Due to the enlargement of the actual exit area for the main stream, the maximal thrust performance is at NPR = 7.0 instead of the designed NPR.

Maturity characterization of soot in laminar coflow diffusion flames of methane/anisole under different oxygen indices

Anisole fuel has gained increased attention, since it is considered a biofuel, and its addition to gasoline increases the octane number, improving the engine performance. This study focuses on the comprehensive characterization of soot maturity and sooting propensity of a well-controlled laminar coflow diffusion flame fueled with anisole and using methane as the carrier gas. Four laminar non-premixed flames were established below the smoke point. The oxidizer composition ranged from a molar fraction of oxygen (oxygen index, OI) of 21% to 35% (doped with pure oxygen), while keeping constant the total volumetric flow rate of oxidizer stream. Multi-wavelength line-of-sight attenuation experiments were performed from visible to infrared wavelengths, and the measurements of the extinction coefficient and flame temperature were used to retrieve two dimensional fields of soot temperature, volume fraction, radiative intensity and degree of soot maturity. In general, the sooting propensity and radiative behavior of the anisole flames follows a similar trend than typical hydrocarbon fuels when increasing the OI. However, the spatial distribution of soot volume fraction is enhanced, particularly near the flame centerline. In contrast, the soot production is promoted by the OI, near the flame wings. The same effect can be observed for the soot temperature. Indeed, temperature increases, promoting formation and oxidation processes, specially at the locations near the maximum soot volume fraction. In general, the maturity of soot particles is affected as the OI is changed. Also, it is observed that the degree of maturity is enhanced by flame temperature. In order to support these local observations, a statistical analysis was carried out. Finally, the results obtained yield a curated database for validating detailed soot production models of oxygenated fuels, and to gain further insights on the evolution of soot maturity and propensity of these particular fuels under different oxidizer conditions.

Progressive Dam-Failure Assessment by Smooth Particle Hydrodynamics (SPH) Method

The dam-break water flow is a complex fluid motion, showing strong nonlinearity and stochasticity. In order to better study the characteristics of the dam burst flood, the smooth particle hydrodynamics (SPH) method was chosen to establish a two-dimensional classical dam-burst model, and the flow velocity distribution graph was obtained by calculation and compared with the experimental results in the literature, and the fitting degree of the two was obtained to be 88.4%, which verifies the validity of the model. On this basis, according to the principle of dam failure, the two failure modes of equal-interval gradual failure and progressive gradual failure were simulated, and the water body characteristics such as water flow velocity, energy, pressure, etc., were analyzed based on the different working conditions of the two modes to obtain the characteristics of gradual dam-failure water flow under the two kinds of numerical models. The simulation results show that, compared with the instantaneous dam failure mode, (1) the flow rate of the dam-failure stream reaching the downstream slows down in the gradual dam-failure mode; (2) the depth development of the breach extends downward in layers and stages over time, and the overall duration of the breach is prolonged; (3) the destructive power of the dam-failure flood is weakened as the number of segments increases. The results of the study show that, compared with the instant dam-failure mode, the calculation results of the breach development considering the progressive gradual dam-failure mode are more in line with the theoretical solution and closer to the actual process of dam failure, which can provide ideas and references for advancing the numerical study of dam failure.

Feasibility of electrodeionization for phosphate removal.

In this study, electrodeionization (EDI) in bath mode was tested regarding its capability to remove phosphate (PO4 3- ) ions from aqueous solutions. Various parameters affecting the phosphate removal rate via EDI were determined. The results showed that the phosphate removal rate depends on the applied voltage and that the optimum potential was 15 V, corresponding to a phosphate removal rate of 97%. Changing the stream rate of the phosphate-containing solution also affected the phosphate removal rate. Changing the pH of the phosphate-containing solution from 2 to 6 enhanced the phosphate removal rate from 80% to 97%. The presence of Cl- , NO3 - , and SO4 2- ions did not affect the phosphate removal rate. The highest mass transfer coefficient (k) of phosphate was calculated to be 7.85 × 10-4 m/s, and the flux was calculated to be 3.72 × 10-4 mol/m2 s1 at a flow velocity of 3L/h. Thus, the study results showed the feasibility of EDI as an alternative membrane process for removing phosphate from aqueous solutions. PRACTITIONER POINTS: Electrodeionization was employed for the removal of phosphate. The removal of phosphate exhibited dependence on applied potential. EDI demonstrated a remarkable 97% efficiency in phosphate removal. The pH of the solution was found to influence the removal rate.

System Design, Optimization and 2nd Law Analysis of a 100 MWe Double Reheat s-CO2 Power Plant at Full Load and Part Loads

Super-critical Carbon dioxide (s-CO2) power plants are considered to be efficient and environmentally friendly compared to the traditional Rankine cycle-based steam power plants and Brayton cycle-based gas turbine power plants. In this work, the system design of a coal-fired 100 MWe double reheat s-CO2 power plant is presented. The system is also optimized for efficiency with turbine inlet pressures and the recompression ratio as the variables. The components needed, mass flow rates of various streams and their pressures at various locations in the system have been established. The plant has been studied based on 1st and 2nd laws at full load and at part loads of 80%, 60% and 40%. Operating parameters such as mass flow rate, pressure and temperature have considerably changed in comparison to full load operation. It was also observed that the 1st law efficiency is 53.96%, 53.93%, 52.63% and 50% while the 2nd law efficiency is 51.88%, 51.86%, 50.61% and 48.1% at 100%, 80%, 60% and 40% loads, respectively. The power plant demonstrated good performance even at part loads, especially at 80% load, while the performance deteriorated at lower loads. At full load, the highest amount of exergy destruction is found in the main heater (36.6%) and re-heaters (23.2% and 19.6%) followed by the high-temperature recuperator (5.7%) and cooler (4.1%). Similar trends were observed for the part load operation. It has been found that the recompression ratio should be kept high (>0.5) at lower loads in order to match the performance at higher loads. Combustion and heat exchange due to finite temperature differences are the main causes of exergy destruction, followed by pressure drop.

An atmospheric pressure plasma afterglow to charge ultrafine aerosol particles

A novel flowing plasma system aimed at increasing charging efficiency of particulate matter and effective removal through electrostatic precipitation is studied. Nanoparticles are passed through the spatial afterglow of an atmospheric pressure radio-frequency glow discharge plasma. Particle charging efficiencies and polarities are measured at different plasma-aerosol gaps, aerosol and plasma flow rates, plasma powers, and afterglow DC bias. Various timescales are calculated to explain the transport of charge carriers that facilitate particle charging processes. The experimental results showed increased charging efficiency and net positive charging at longer gaps between the afterglow and aerosol stream and lower aerosol flow rates. Timescale analysis indicates that when ample residence time is provided, transport of charge carriers shifts from ambi-polar diffusion to free diffusion, and electrons are rapidly lost from the afterglow, resulting in highly efficient, net positive charging of particles. The charging efficiency of particles in optimized operating conditions was comparable or higher than reported collection efficiencies of electrostatic precipitators. The findings overall demonstrate that glow discharges are capable of charging particles not immersed in the plasma bulk, and such systems show promise for improving performance of particle mitigation technology.

A 3-dimentinal CFD model for simulation of an O2/N2 separation process using an industrial PIHF membrane module for N2 enrichment

In this research, simulation of an O2/N2 membrane separation process for N2 enrichment using an industrial polyimide hollow fiber (PIHF) membrane module was performed based on finite element method. A 3-dimensional (3D) model was used to simulate the mass transfer, convection and diffusion phenomenon in the membrane module. In order to validate the model, the simulation results were compared with the industrial process data, and good agreement was observed. The effects of feed molar flow rate, feed pressure, and molar flow rate of sweep gas stream on the N2 enrichment percentage were investigated. As discovered, the N2 enrichment percentage is improved by enhancing the feed pressure and sweep gas flow rate, while an increase in feed flow rate promotes a diminish in percentage of N2 enrichment. Besides the operational parameters, the influence of flow patterns (co-current and counter-current) and fiber length on the N2 enrichment in lumen side and gas molecules distribution in the membrane side of PIHF membrane module was investigated respectively. As the fiber length increased, the N2 enrichment percentage augments for both patterns due to membrane surface area increment in the PIHF membrane module, which the percentage of N2 enrichment in the countercurrent pattern was higher than co-current. Moreover, Concentration Polarization Index (CPI) was investigated to show the degree of polarization expansion along the PIHF membrane. The effect of feed molar flow rate on the concentration polarization index was investigated, which showed that concentration polarization phenomenon is reduced when feed molar flow rate enhances.

Ignition Investigation of Pure Biodiesel in A Research Engine with Dual Fuels

Under the effect of acetylene (C2H2) as a secondary energy in diesel engines powered by Acacia methyl ester (ABD) is investigated in this study. This experimental work is carried out on single cylinder, water cooled, direct injection diesel engine. At the intake manifold air and C2H2 was combined and mixture will have specific stream rate (2 and 4 lpm). In a diesel engine, the ignition analysis of changed fuels under varied Mean Effective Brake Pressure (BMEP) is assessed and contrasted with diesel by adjusting the apparatus load between 01 and 05 BMEP. This research looks at C2H2 as a sustainable twin fuel with the goal of lowering diesel apparatus emissions while improving performance. Experiments demonstrated that supplying C2H2 at 2 and 4 Litres per minute (lpm) results in faster flame velocity and greater flammability for ABD, resulting in enhanced efficacy and improved combustion patterns. Because of its higher flammability and longer C-H chain, acacia methyl ester with acetylene (ABD-C2H2) at 2 lpm and ABD-C2H2 at 4 lpm reduced hazardous diesel motor exhaust compared to biodiesel alone. According to the findings of this investigation, adding acetylene at varied flow rates improves biodiesel's ignition patterns in a diesel engine with no changes.

Artificial intelligence based prediction of optimum operating conditions of a plate and fin heat exchanger under uncertainty: A gray-box approach

This study is based on gray-box modeling for the prediction of optimum mass flow rates of inlet streams of a Plate and Fin Heat Exchanger under uncertainty. A first principle model of the Plate and Fin Heat Exchanger was developed in Aspen Exchanger Design and Rating. Genetic algorithm was integrated with the first principle model to achieve the highest possible exit temperature of the cold process stream under uncertainty. A dataset of uncertain process conditions and their corresponding optimum inlet flow rates derived through the first principle-genetic algorithm integration was used to develop an artificial neural networks model. The artificial neural networks model was then integrated with the first principle model by replacing the genetic algorithm to form a novel gray-box framework. The proposed gray box model, i.e., artificial neural networks and first principle integration, achieved a higher effectiveness and higher outlet temperature than those derived through the straight run first principle model. The performance of the gray box framework was also comparable to the first principle integrated genetic algorithm approach and significantly minimized the computation time needed for estimating the optimum process conditions. First principle integrated genetic algorithm approach enhanced the effectiveness of the straight run model by 3.05%. Performance of the proposed gray-box model was comparable to the integrated framework of the genetic algorithm with the first principle model but was significantly faster. The developed artificial neural networks model was employed as a surrogate in Sobol and FAST sensitivity analysis framework to identify the impact of input variables on output variables. The proposed gray box based method enhanced the capability of the plate and fin heat exchanger to recover energy from the process stream and its robustness to cope with uncertainty. The proposed approach is suitable for real-time application and would contribute to laying a foundation for petroleum refinery 4.0.

Effect of muzzle gas on forward blood spatter from a gunshot: Experiments with a supersonic de Laval nozzle

For bloodstain pattern analysis (BPA), interpreting statistically reliable data on a crime scene resulting from gunshots is a great challenge. This is due to various uncertainties, including blood rheology, hematocrit, coagulation, surrounding atmospheric conditions, victim's peculiarities, gun types, geometries, etc. In addition, muzzle (propellant) gases that follow the bullet may influence the aerodynamics of blood spatter in the cases of short-range shooting. We studied the muzzle gas effect on forward blood spatter. Muzzle gas can penetrate the wound channel and be ejected from the bullet exit hole affecting the forward blood spatter. Experiments with blood atomization by a gas flow issued from a supersonic de Laval converging–diverging nozzle are conducted. Defibrinated sheep blood was enclosed in a thin solid cylinder, which was filled by a supersonic air flow ejected from a de Laval nozzle, mimicking the muzzle gas flow through a wound channel. The mass flow rate of the supersonic air stream was varied by controlling the upstream chamber pressure. It was found that the number counts of the forward blood spatter from the muzzle gas blasting peaked at relatively shorter distances from the exit hole compared to the one that would be caused by a bullet. The effects of the muzzle gas and bullet could cause the formation of a bimodal spatter distribution on the floor behind the exit hole. These findings imply that atomization events owing to muzzle gas cause coarser atomization than that of a bullet, which could facilitate BPA in distinguishing certain homicides from staged suicides.

Environmental DNA (eDNA) removal rates in streams differ by particle size under varying substrate and light conditions

The use of environmental DNA (eDNA) as a sampling tool offers insights into the detection of invasive and/or rare aquatic species and enables biodiversity assessment without traditional sampling approaches, which are often labor-intensive. However, our understanding of the environmental factors that impact eDNA removal (i.e., how rapidly eDNA is removed from the water column by the combination of decay and physical removal) in flowing waters is limited. This limitation constrains predictions about the location and density of target organisms after positive detection. To address this question, we spiked Common Carp (Cyprinus carpio) eDNA into recirculating mesocosms (n = 24) under varying light (shaded versus open) and benthic substrate conditions (no substrate, bare substrate, and biofilm-colonized substrate). We then collected water samples from each mesocosm at four time points (40 min, 6 h, 18 h, and 48 h), and sequentially filtered the samples through 10, 1.0, and 0.2 μm filters to quantify removal rates for different eDNA particle sizes under varying light and substrate conditions. Combining all size classes, total eDNA removal rates were higher for mesocosms with biofilm-colonized substrate compared to those with no substrate or bare (i.e., no biofilm) substrate, which is consistent with previous findings linking biofilm colonization with increased eDNA removal and degradation. Additionally, when biofilm was present, light availability increased eDNA removal; eDNA levels fell below detection after 6–18 h for open mesocosms versus 18–48 h for shaded mesocosms. Among size classes, larger particles (>10 μm) were removed faster than small particles (1.0–0.2 μm). These results suggest that changes in the distribution of eDNA size classes over time (e.g., with downstream transport) and with differing environmental conditions could be used to predict the location of target organisms in flowing waters, which will advance the use of eDNA as a tool for species monitoring and management.

Estimating sheet erosion on purple soil hillslope treated with polyacrylamide (PAM) in the Three Gorges Reservoir area

Study regionThe Three Gorges Reservoir area (TGR), China Study focusSoil erosion on purple soil hillslope and its negative effects are deleterious to the ecological environment of the TGR. Sheet erosion is the initial form of the slope erosion, which is notably impacted by land degradation, polyacrylamide (PAM) is commonly applied for soil and water conservation purpose, while the sheet erosion on purple soil hillslope treated with PAM remains unclear. New hydrological insights for the regionThe findings suggested that the sheet erosion and runoff rate increased as the rainfall intensity was increased and the slope gradient was decreased with increasing PAM application rate until reaching minimum values at 0.80 g m−2, and these quantities increased afterward. The single and combined impacts of the PAM application rate, rainfall intensity and slope gradient on erosion and runoff were significant. The slope gradient, rainfall intensity and PAM application rate also influenced the hydrodynamic parameters, and the stream power was the optimal parameter for describing the sheet erosion. An equation encompassing the rainfall intensity, slope gradient and PAM application rate was used for sheet erosion rate prediction with high accuracy relative to the stream power and PAM application rate. These results could be helpful to better understand sheet erosion on purple soil slopes treated with PAM and offer fundamental guidelines for soil and water conservation in the TGR.

Anchored and Lifted Diffusion Flames Supported by Symmetric and Asymmetric Edge Flames

Numerous combustion applications are concerned with the stabilization of diffusion flames formed by injecting gaseous fuels into a co-flowing stream containing an oxidizer. The smooth operation of these devices depends on the attachment and lift-off characteristics of the edge flame at the base of the diffusion flame. In this paper, we address fundamental issues pertinent to the structure and dynamics of edge flames, which have attributes of both premixed and diffusion flames. The adopted configuration is the mixing layer established in the wake of a splitter plate where two streams, one containing fuel and the other oxidizer, merge. The analysis employs a diffusive-thermal model which, although it excludes effects of gas expansion, systematically includes the influences of the overall flow rate, unequal strain rates in the incoming streams, stoichiometry, differential and preferential diffusion, heat loss and gas–solid thermal interaction, and their effect on the edge structure, speed, and temperature. Conditions when the edge flame is anchored to the plate, lifted-off and stabilized in the flow, or blown-off, are identified. Two stable modes of stabilization are observed for lifted flames; the edge flame either remains stationary at a specified location or undergoes spontaneous oscillations along a direction that coincides with the trailing diffusion flame.

Validation of a Cost-Effective RP-HPLC Method for Quantitative Investigation of Daclatasvir Dihydrochloride in Pharmaceutical Formulations

A well-known direct-acting antiviral (DAA) drug called daclatasvir may be used to treat chronic hepatitis C virus (HCV) infection. Herein, we reported a selective, precise, and a cost-effective analytical method for the measurement of an active pharmaceutical ingredient (API) of daclatasvir dihydrochloride in drug substances as well as drug products via the reversed-phase RP-HPLC technique. To obtain greater separation, the majority of the chromatographic conditions were improved. Best separation findings were achieved under chromatographic conditions with an HPLC column of USP L1 (150 × 4.6 mm, 5 μm) by utilizing a combination of acetonitrile and buffer solution of KH2PO4 (30 : 70, v/v) as a mobile phase at a stream rate of 1 mL.min−1 with a finding at 300 nm and a column temperature of 40°C. Linearity was examined in the range of 90–210 ppm (R2 = 0.999) for daclatasvir dihydrochloride. The new technique has been verified using industry-recognized criteria, including applicability, system precision, accuracy, robustness, specificity, range, linearity, quantification limit, reagent stability, and detection limit. All the measured metrics were determined to be within acceptable limits using the criteria of the Worldwide Council for Harmonisation (ICH). In pharmaceutical labs, daclatasvir dihydrochloride may be analyzed qualitatively and quantitatively using the well-established RP-HPLC technique. Our study also highlights the need to evaluate the greenness of the method developed using a recognized tool ,i.e., Analytical Greenness Metrics (AGREE).

Effectiveness of temperature and humidity treatment processes: Unified expression and thermodynamic analysis

Temperature control and humidity control are the two main objectives of the heating, ventilation, and air conditioning (HVAC) system. Previous studies have mainly focused on analyzing one or more existing configurations with regular indoor conditions of public and residential buildings. In this study, a unified expression is derived to evaluate the thermodynamic effectiveness from the ideal temperature and humidity treatment processes to the actual cooling and dehumidification systems, and it is modified by progressively rejecting the “ideality” assumptions. It is indicated that the thermodynamic effectiveness of the ideal temperature and humidity treatment process only depends on the initial state, the final state, and the flow rate of the air streams, and the process with the highest COPth for dehumidification is coupled with the cooling process. Based on the illustrative non-ideality characteristics in the actual cooling and dehumidification systems, the exergy performances of multiple system configurations are investigated. The results also elucidate that the liquid desiccant systems attain less irreversible loss and has a relatively high thermodynamic effectiveness, but the desiccant wheel system also shows great potential for deep dehumidification applications. This research provides a theoretical guide and illustrates the potential paths for the future design of exergy efficient cooling and dehumidification systems.

Pressure loss control in a rotor-stator cavity with inward throughflow

The back cavity of a centrifugal impeller is a typical rotor-stator cavity system with centripetal inflow in small or medium-sized aeroengines. In this paper, the effectiveness of using the “vortex control hole” structure to control the pressure loss in such a cavity is studied with experiment and numerical simulation. Vortex control hole refers to the passage connecting the internal and external air flow of the cavity. It distributes on the stationary casing circumferentially with a well-designed angle to produce an opposite tangential velocity to the main flow, thus reducing the tangential velocity of the main flow in the cavity. By controlling the swirl ratio, the pressure loss at cavity outlet could be decreased. The rotating Reynolds number Re φ = 6 × 105∼2.4 × 106, and turbulence parameter λt = 0.21∼0.55. Since the mainstream velocity has no tangential component at the inlet, it is considered that the inlet swirl ratio β0 is 0. The numerical simulation results were compared with the experimental results. The flow structure, the distribution of the swirl ratio, and the static pressure loss at the outlet of the cavity under different secondary air stream rates will be given. The coupling mechanism between the secondary airflow and the main flow in the cavity and the mechanism of the secondary air stream reducing the pressure loss in the disc cavity will be analyzed.

Performance study of CrN coatings prepared by DC magnetron sputtering

Cutting edge declaration strategies and the progression of advanced troublesome coating materials are fundamental for the making of high-quality mechanical components. The point of this work is to induce prepared CrN coatings by magnetron sputtering at unmistakable nitrogen stream rates and to look at the effect of moving nitrogen stream rates on the composition, film thickness and mechanical properties of the gotten chromium nitride coatings. The outcomes appear that the nitrogen stream rate impacts the sputtering rate of the coating, i.e. the affirmation rate diminishes as the degree of nitrogen interior the plasma increments. In expansion, as the nitrogen stream rate increments, the grain gage of the coating diminishes, and the hardness modulus of the coating increments. Flexibility data illustrate that extending the N2 stream rate increases the wear resistance and flexibility of the coating.

Transmissive Reconfigurable Intelligent Surface Transmitter Empowered Cognitive RSMA Networks

In this paper, we investigated the downlink transmission problem of a cognitive radio network (CRN) equipped with a novel transmissive reconfigurable intelligent surface (TRIS) transmitter. In order to achieve low power consumption and high-rate multi-streams communication, time-modulated arrays (TMA) is implemented and users access the network using rate splitting multiple access (RSMA). With such a network framework, a multi-objective optimization problem with joint design of the precoding matrix and the common stream rate is constructed to achieve higher energy efficiency (EE) and spectral efficiency (SE). Since the objective function is a non-convex fractional function, we proposed a joint optimization algorithm based on difference-of-convex (DC) programming and successive convex approximation (SCA). Numerical results show that under this framework the proposed algorithm can considerably improve and balance the EE and SE.

Queuing system without queue and deterministic service time

Today, queueing systems that describe failures in the process of software testing are subject to extensive research. Such systems involve a dependence between the rate of an input Poisson stream and the rate of exponentially distributed handling time. Using this dependence, system load levelling procedures are defined. However, such a model and method of research are not suitable for systems with a deterministic handling time. Therefore, this paper examines the dependence of the Poisson distribution parameter of the number of requests in a system from the deterministic handling time in the presence of a peak rate of the input stream. This dependence is examined analytically and numerically. It is shown that a reduction of the handling time levels the peak number of customers in the system

Improvement and evaluation of hydrodynamic conditions in plain regional drainage systems by artificial lakes: a case study of Xinxiang Economic Development Zone, China.

With the development of the city, people pay more attention to the ecological construction of the city. The objective of this work was to study the effect of artificial lakes on hydrodynamic conditions in urban drainage systems. With Arcgis and the advantage of SWMM in analyzing the impact of the rainfall process on urban runoff, the urban flooding model of "pipe network + river network + artificial lake" was established in the study area. Two scenarios were set up with and without the presence of artificial lakes, and comparative analyses were conducted under the different intensities of rainfall (0.5a, 1a, 2a, 5a, 10a, 20a). The results show that under certain rainfall conditions, the presence of the artificial lake increases the peak flow and rate of upstream streams and decreases the flow and rate of downstream streams in the regional drainage system. The duration of the peak flow rate in the upstream channel increases, and the flow rate curve becomes flat during the confluence; the flow rate in the downstream section decreases, and the magnitude of the peak flow rate change decreases, and a more obvious horizontal section appears. The time of peak occurrence in the downstream river is earlier. The hydrodynamic impact on the downstream channel is more significant. The improvement of hydrodynamic conditions of the drainage system by the artificial lake helps to optimize the layout of low impact development (LID) measures in the study area and also guides ecological construction in other cities.