Flow Coefficient Research Articles

Numerical investigation of inlet-pipe configurations on fluid dynamics and flow-field characteristics inside filling valve

The filling valve requires high efficiency and stability in the working process, which is closely related to the distribution of the flow characteristics inside the valve. In this study, computational fluid dynamics (CFD) methods were present to analyse the pressure, velocity, and other characteristics of the filling valve under different inlet pipe angles and valve openings. The flow characteristics, which are experimentally measured, are consistent with CFD simulation results. Research shows that the increase in the angle of the inlet pipe can improve the uniformity of the flow field inside the valve, produce a better core flow pattern at the valve outlet, and have better fluid stability. Based on the flow characteristics of the valve, to obtain good filling efficiency and stability, a moderate valve opening of 9 mm should be selected, and the flow coefficient can reach 1.08, which is 1.6 times higher than that of 3 mm, and the angle of the inlet pipe should be appropriately increased. This study provides a reference for the use and optimization of filling valves.

Flow characteristics and resistance coefficients of local components of building heat-moisture-oxygen transport pipelines in the Tibetan Plateau

The Tibetan Plateau is characterized by low-pressure, cold, hypoxic, and dry ambient conditions. Thus, in addition to heating, buildings in the region need humidification and oxygenation. It is noted here that the existing specifications of the resistance coefficients of the gas flow in the HVAC pipeline do not consider the effect of the variation in air components on the local resistance of the pipeline due to the low air pressure conditions as well as the humidification and oxygenation. In this paper, the effects of various parameters on the local resistance loss are investigated and reported, including the atmospheric pressure, inlet velocity, humidity, oxygen concentration, pipe diameter, wall roughness, velocity ratio, and area ratio between the branch and the main pipes. The results showed that the decrease in atmospheric pressure leads to a shorter longitudinal distance of effective dissipation of the secondary flow, primarily concentrated in 25D-27D. Additionally, the resistance losses generated in the elbow, the tee straight branch pipe, and the side branch pipe are reduced, with a maximum reduction of 42 %, 33 %, and 46 %, respectively, under low pressure conditions. Also, with the increase in the inlet velocity and the decrease in the pipe diameter, the local resistance of the elbow pipe is increased by a maximum of 14 times and 22 %. Moreover, when the velocity ratio increases and the area ratio between the branch pipe and the main pipe decreases, the local resistance loss of the straight branch pipe and the side branch pipe increases. Based on this study, the recommended value of the local resistance coefficient of the elbow and tee under low pressure is identified. This can provide a reference for the proper design of heat-moisture-oxygen transport pipelines in the plateau area.

Effects of rotational speed on transient cooling performance of nozzle spray with liquid nitrogen in a rotor-stator cavity

This paper presents the results of an experimental investigation into the cooling performance of a rotor-stator cavity with liquid nitrogen spraying. The experiments were conducted under varying rotational Reynolds numbers ranging from 1.70 × 106 to 5.12 × 106. The effects of rotational speed on temperature drop rate are studied and compared in detail, as well as the heat transfer coefficient distribution. Sufficient data, such as heat flux, injection rate, and injection pressure, were collected to provide a basis for further study in explaining the spray and evaporation over the cavity. It was found that the cooling performance of the rotating disc is strongly affected by the rotational speed. The short-term period exhibits a peak cooling rate of 14°C/s, in contrast to the sustained cooling rate during the spray process at rotational speeds of 500r/min, which amounts to 0.9°C/s. The occurrence of cavitation and evaporation within the nozzle results in a reduction of flow coefficient and fluctuation of the injection differential pressure. The transient cooling performance is well-explained by the temperature changes and cooling-down time under different rotational speeds. The analysis of the heat transfer coefficient is further enhanced through an evaluation of the convective and conductive heat transfer rates using a one-dimensional theoretical approach. The average temperature of the disc is expected to decrease by 100°C within a time frame no longer than 120 s. Additionally, after a duration of 120 s, the average heat transfer rate on the cold side is anticipated to surpass 8000 W/(m·K).

Fundamental heat and entropy transfer mechanisms of convection underlying the first and second laws for an unsteady multiport system and their applications in parallel flow heat exchangers

Although thermal convection is ubiquitous in nature and technology, it has long been argued whether convection can be considered as an independent mode of heat transfer. Here, we show that pure convection mode is generally recognized from the classical first and second laws via mass flow by rooting the unsteady mass conservation relation through an equivalent multiport system. The fundamental distinction is made between convection driven by the thermal and entropy potential differences and mass flow accompanied by zero potential difference. The constitutive relations of the convective heat and entropy fluxes and their thermodynamic relationship are developed in terms of their potential differences with the exponential distribution of temperature difference in a compressible flow. In the absence of work transfer, the first and second laws are simply expressed by the standard Maxwell’s electromagnetic type equations via the total heat and entropy flux vectors. The pure convection theory is applied to a parallel-flow heat exchanger and the linear temperature difference distribution is obtained for both streams via the first-law definitions of the convective and overall heat transfer coefficients in an internal flow. The entropy generation rate inside a heat exchanger is recalculated and indicated to be driven by the difference between the reciprocal of outlet temperatures of two streams, from which the entropy generation number between outlets is developed to eliminate the entropy generation paradox. The present linear temperature difference profiles agree well with the experimental data, and the outlet entropy generation number is also justified by comparing with the previous nondimensionalizing entropy generation numbers.

Draft-free air conditioning through split membrane ceiling system: An exploratory study

The draft caused by convective air-conditioning is a primary contributor to thermal discomfort, particularly in localized cooling scenarios. While radiant systems offer a windless alternative, their condensation risks and maintenance costs bring concerns. In response, our research proposes an air-based radiation-convection hybrid system that’s draft-free and easy to implement. By suspending a breathable, flexible, textile-based membrane beneath the ceiling, the system mitigates drafts from ceiling-mounted air conditioners and leverages the membrane’s vast surface area for radiation. This work is an exploratory study focused on a retrofit split membrane system laying below the commercially packaged air conditioner (PAC). Three independent experimental studies were conducted. The first is a full-scale experiment assessing the membrane’s impact on PAC system operation and heat load management. The second is fundamental research to determine the permeation and airflow deceleration properties of different membranes. The third is a practical assessment in a self-study room retrofitted with the split membrane, aiming to determine the possibility of maintaining draft-free conditions. Results indicate that membranes with high laying ratios risk airflow short-circuiting. It can be reduced by adjusting the laying ratios and altering the laying pattern of the membrane, which also improves perimeter heat load management. Moreover, the permeation characteristics of various membrane materials were examined through flow and velocity attenuation coefficients. Besides material considerations, preliminary observations suggest that the membrane’s curvature could influence its permeation. Furthermore, the temperature and velocity data preliminarily affirmed the anti-draft performance of the split membrane ceiling system.

Probing Relativistic Heavy-Ion Collisions via Photon Anisotropic Flow Ratios. A Brief Review

The anisotropic flow of photons produced in relativistic nuclear collisions is known as a promising observable for studying the initial state and the subsequent evolution of the hot and dense medium formed in such collisions. The investigation of photon anisotropic flow coefficients, vn, has attracted high interest over the last decade, involving both theory and experiment. The thermal emission of photons and their anisotropic flow are found to be highly sensitive to the initial state of the fireball, where even slight modifications can lead to significant variations in the final state results. In contrast, the ratio of photon anisotropic flow stands out as a robust observable, exhibiting minimal sensitivity to the initial conditions. Here, we briefly review the studies of the individual elliptic and triangular flow parameters of photons as well as their ratios and how these parameters serve as valuable probes for investigating the intricacies of the initial state and addressing the challenges posed by the direct photon puzzle.

An approach for topology optimization of heat sinks for two-phase flow boiling: Part 1 – Model formulation and numerical implementation

Two-phase flow boiling in heat sinks and cold plates is attractive for various thermal management applications due to high effective heat capacity rates and high heat transfer coefficients compared to single-phase operation. In addition, multi-physics topology optimization is sought for generation of high performance thermal management components. Yet, the design of heat sinks using topology optimization has been restricted to single-phase flow physics, due to incompatibility between available two-phase flow models and traditional single-phase topology optimization approaches. Interface-capturing two-phase flow models are too computationally expensive for optimization; mixture and two-fluid models that treat the liquid and vapor phases as an interpenetrating continuum with interfacial transport phenomena captured through empirical correlations are computationally tractable for heat-sink-scale optimization. However, the penalization approaches commonly used to define the structures formed during topology optimization results in arbitrary fin and channel geometries for which a universal two-phase flow correlation is not available. To enable coupling with two-phase mixture models, this work leverages a homogenization approach to topology optimization wherein heat sink designs are represented using spatially varying microstructures with optimized dimensions. A predefined microstructure geometry is chosen for which two-phase flow correlations exist and therefore topology optimization can be performed. This work is the first to develop a topology optimization algorithm using a mixture model for simulating two-phase flow boiling to design heat sinks and cold plates. Part 1 of this study develops and implements the algorithm to investigate topology optimized heat sinks at various heat inputs, topology optimization grid sizes, and maximum vapor quality constraints. Topology optimized heat sinks designed for single-phase versus two-phase flow are compared. There are significant differences in hydraulic and thermal responses of the single-phase and two-phase designs due to high effective heat capacity rates and high heat transfer coefficients of flow boiling. A companion paper (Part 2) focuses on manufacturing, model calibration, and experimental validation of the topology optimized heat sinks under two-phase flow boiling. The algorithm demonstrated in this work extends the capabilities of topology optimization to two-phase flow physics, and thereby enables the design of various two-phase flow components such as evaporators, condensers, heat sinks, and cold plates.

Numerical simulation of the internal flow field for the new three-way changeover valve

This article uses numerical simulation methods to simulate the internal flow field of a new three-way changeover valve structure, and verifies the simulation results through flow experiments. The results show that the flow coefficients on the handwheel side and opposite side of the new changeover valve obtained by the simulation method are within 10% of the experimental results, indicating that the results obtained by the simulation method can better match the experimental results. In addition, the flow coefficients on the handwheel side and opposite side of the new three-way changeover valve have increased by 49.6% and 64.3% respectively compared to the existing structure, indicating better flow capacity.

Assessing the water potential and wastewater load capacity of the La Tinh River, Binh Dinh province by MIKE 11AD and Ecolab model combined with GIS method

The study used the NAM model of flow simulation with a time series of 14 years (2008 - 2021), statistical analysis method, and MIKE 11 AD water quality model, and Ecolab combined with GIS method to calculate wastewater reception capacity and load capacity of the basin. The model validation is highly reliable with a model efficiency factor of R2 of 0.777 and BIAS = 5%. The results of the application of the NAM model have determined the daily flow series of 14 years (2008 - 2021) and the average flow characteristics of many years of the La Tinh basin such as Qo flow is about 5.9; 6.0 m3/s, total amount of Wo = 292.1; 188.8 million m3 flow modulus Mo = 19.3 l/s-km2 flow class Yo = 611 mm and flow coefficient α= 0.3 for all sub-basins. The results of the study show that the capacity of receiving wastewater, the capacity of most river sections in the La Tinh basin is still received with five parameters at a relatively high level, the section of the Binh Tri river upstream alone has exceeded its capacity to receive. This is one of the very useful tools in integrated management and effective use management of river basin water resources.

Prediction of heat transfer coefficient and pressure drop of flow boiling and condensation using machine learning

Heat transfer coefficient and pressure drop are two critical parameters in diverse thermal engineering applications, and the prediction of these parameters plays a crucial role in the development of heat exchangers. Traditional methods are often reliant on empirical correlations based on limited refrigerants and experimental conditions. The present research explores the application of machine learning methods to predict the heat transfer coefficient and pressure drop of a wide range of pure and mixed refrigerants. The methodology involves the compilation of over 20, 000 experimental observations encompassing an extensive range of operating conditions, heat exchanger geometries, and refrigerants. A total of 27 machine learning algorithm models, such as regression tree, support vector machines, and deep neural networks, are trained on this diverse dataset to discern intricate patterns and dependencies. After dividing the dataset into 80% for training and the rest for validation, the machine learning prediction shows an ability to predict the heat transfer coefficient and the pressure drop with high accuracy in most of the refrigerants. Notably, the accuracy achieved by the machine learning models surpassed that of conventional correlations, highlighting their superior predictive capabilities. Furthermore, the accurate prediction of heat transfer enhancement methods added another layer of validation to the model’s effectiveness. It is noteworthy that the dataset employed in this study has been made publicly accessible online.

Performance Envelope of a 538-Series High-Speed Helico-Axial Pump for High-Gas-Volume-Fraction Operation

Summary Operating at high speeds can have the benefit of increasing the capability of pumps to enhance surface or downhole production of fluids with high gas volume fraction (GVF). This study presents the performance envelope of a high-speed helico-axial pump (HAP) operating at high GVFs (>80%). The ultimate aim of the physical tests was to ascertain the operating capabilities of the pump for potential scaleup to a field prototype. The HAP housing outer diameter was 5.38 in. and operated at a rotational speed of 6,000 rev/min. Air and water were the test fluids, with an average pump intake and a discharge temperature of 28°C. The fluid volume flow rates were varied while maintaining 46 psig at the HAP intake. The liquid and total intake volume flow rates varied from 128 B/D to 664 B/D and 4,941 B/D to 7,593 B/D, respectively. The corresponding dimensionless pressure boost (DPB), GVF, liquid flow coefficients (LFCs), and total flow coefficients (TFCs) were recorded. Additional parameters noted were the percentage of electric current draw to full-load motor current by the HAP motor and the percentage of electric power input to full load power to the HAP motor. The results showed that the HAP had a stable operation during the tests for intake GVF range of 91–98%. The corresponding pump DPB was in the range of 0.0138–0.0751. These values being positive indicated the capability of the HAP to boost fluid pressure even for such high intake gas content and avoid pump gas lock. The results also showed that for a given intake GVF, the HAP DPB increased with decreasing LFC. For a given LFC, the DPB decreased with increasing intake GVF. The percent electric input power to the HAP motor varied between 28% and 64% of full-load motor power. It was observed to strongly increase with decreasing LFC at a given intake GVF and very strongly decrease with increasing intake GVF at a given LFC. The associated percent electric current draw by the HAP motor was seen to vary between 24% and 53% of full-load motor current. Its variation with LFC and intake GVF was similar to those of the percent electric power input. The DPB, percent electric current, and power draw by the HAP motor variations with TFC for a given intake GVF were similar to those of the LFCs. In conclusion, the HAP demonstrated the capability to boost fluid pressure when handling high GVF flows. It is being scaled up to a field prototype to handle higher volume flow rates of high GVF gas-liquid mixtures. This study mainly highlights the method to extend the gas-handling capability of a HAP by operating it at high speeds. Optimal hydraulic design and proper conditioning of the inlet flow components were also incorporated into the HAP architecture. Expanding the HAP operating envelope to handle high-GVF flows significantly unlocks the potential for field operators to maximize hydrocarbon production from high-gas content applications. This, in turn, increases the economic bottom line from the field asset.

Numerical Investigation of Butterfly Valve Performance in Variable Valve Sizes, Positions and Flow Regimes

Reliability and efficiency of valves are necessary for precise control and sufficient heat-flow to heat application plants for the integrated energy systems of nuclear power plants (NPPs). Strategic Management Analysis Requirement and Technology (SMART) valves’ ability to control flow and assess environmental parameters stands out for these requirements. Their ability to sustain the downstream flow rate, prevent reverse flow, and maintain pressure in the heat transport loop is much more efficient with the integration of sensors and intelligent algorithms. For assessing valve performance and monitoring, mechanical design and operating conditions are two important parameters. In this study, the butterfly valves of three different sizes are simulated with water and steam using STAR-CCM+ in various flow regimes and positions to analyze performance parameters to strategize an automated control system for efficiently balancing the heat–transport network. Also, flow behavior is studied using velocity and pressure fields for valve–body geometry optimization. It can be observed, through performance parameters, that the valves are suitable for operation between 30° and 90° positions with significantly low loss coefficients and high flow coefficients, and the performance parameters follow a certain pattern in both water and steam flow in each scenario.

JUSTIFICATION OF NOZZLE PARAMETERS OF JET-TYPE WASHING MACHINES FOR CLEANING AGRICULTURAL MACHINES AND UNITS

Agricultural machinery and equipment are exposed to significant contamination by various types of pollutants, some of which can be easily removed, while others require the use of special cleaning agents and machines. To remove these contaminants, a pressurized water jet is used, the biggest disadvantage of such devices is the significant water consumption, so the issue of intensifying the cleaning process of agricultural machinery using a limited amount of water is an important scientific task. Cleaning of agricultural machinery and units from contaminants is a complex technological operation, therefore, there is a need to develop and justify the parameters and operating modes of a high-tech washing device that would ensure high-quality removal of all types of contaminants with high efficiency, minimal water consumption and minimal labor costs. The analysis of cleaning technologies showed that water jet cleaning is the most promising for removing dirt from the surface of agricultural machines and units, the technology allows to increase the level of mechanical impact by using additional energy, which can be the energy of a rotating jet. The study examines the efficiency of cleaning washing plants from various contaminants. The main focus is on studying the impact of nozzle design on the quality and productivity of the washing process. Nozzles determine the shape of water jets and their velocity, determining the cleaning efficiency. The dagger and fan nozzles, their advantages and disadvantages are considered. Nozzle parameters such as orifice diameter, spray angle, and number of fan jets are investigated. It is shown that properly selected nozzle parameters play an important role in achieving the optimal cleaning effect and water saving. Factors such as flow coefficient, drag coefficient, and velocity coefficient that affect the performance and energy of the jet are outlined.

Effect of wettability on fracturing fluid microscale flow in shale oil reservoirs

The wettability of shale reservoirs has an important influence on the flow of external fluids. In this paper, the effect of wettability on the self-absorption of hydraulic fracturing fluid under different pore size conditions is first analyzed. Then, the mechanism of the influence of wettability pore size on the flow coefficient is elucidated. The results show that (a) as the pore size decreases, the importance of various forces acting on the fluid during the flow process changes, and the solid-liquid interaction will greatly affect the fluid flow in the nanopore. (b) When the radius is 5, the flow enhancement increases from 0.6331 to 0.998 as the radius increases from 0 to 3.141594.(c) The shale inorganic material contains a variety of minerals, and the interaction forces between different mineral surfaces and water molecules are different, resulting in different apparent viscosities.

An experimental approach to heat loss measurement of horizontal two-phase flow boiling in low-pressure low-flow (LPLF) conditions

A crucial parameter remarkably influencing the reliability and accuracy of vapor quality measurements in flow boiling experiments is the measurement of heat loss. The latent heat loss estimation in two-phase flow boiling sounds more demanding than that of sensible heat loss in single-phase flow experiments. To accurately investigate the impact of vapor quality on the heat transfer coefficient of flow boiling, accurate estimates of heat loss and subsequent calibration of heat supplies are of a great significance. It is widely common that the single-phase flow tests are performed to estimate a fixed heat loss percentage and calibrate heat supplies for further measurements of vapor quality and heat transfer coefficient of flow boiling experiments. In the present work, an empirical methodology is first proposed to measure heat losses and calibrate latent heat supplies directly from flow boiling process. The proposed methodology is then compared and verified with the commonly applied methodology which uses single-phase flow experiments. The proposed methodology exhibited higher accuracy than the single-phase-based methodology to estimate heat losses and measure vapor quality within two-phase flow boiling under low-pressure low-flow (LPLF) operating conditions.

A prediction model based on data-driven method for velocity and heat transfer coefficient of falling-film liquid on horizontal tube

The prediction of liquid film velocity and heat transfer coefficient of horizontal-tube falling-film flow is important for the investigation and enhancement of the flow and heat transfer behavior. To date, the prediction mainly relies on semi-empirical-semi-theoretical formulas based on data fitting. This prediction method has many limitations and assumptions on working conditions, and the error is large when it is extended to practical applications. In this paper, a support vector regression machine prediction method based on sine cosine algorithm optimization is proposed to improve the prediction accuracy of the liquid film velocity and heat transfer coefficient. And the database was established by conducting horizontal-tube falling-film flow and heat transfer experiments. Results show that the support vector regression model has the best prediction performance with small sample size in comparison with other four machine learning methods and traditional correlation based on Least Square method. The RMSEs of liquid film prediction model and heat transfer prediction model are only 0.0281 and 0.0117 respectively. And the MAPEs are 8.58 and 2.63 respectively. The liquid film velocity and heat transfer coefficient were accurately predicted based on relevant parameters. The importance of these parameters was also analyzed.

Variability of Double-Porosity Flow, Interporosity Flow Coefficient λ and Storage Ratio ω in Dolomites

Seventy-one pumping tests were carried out in various dolomites, revealing two of the less-studied hydrogeological parameters related to double-porosity flow: the interporosity flow coefficient λ and the ratio between storage in the fractures and storage in the whole system (ω). Conceptually, they are both tied to the flow properties of the fractures and matrix and define the communication between these two hydrogeological domains. Five different groups of dolomites were included in this study, with different diagenesis types, crystal sizes, bed thicknesses, fracture intensities and chert contents represented. The results of both parameters reflect variations in the sedimentological and resulting hydrogeological properties of dolomites. The largest values of the interporosity flow coefficient λ (6.53 × 10−1) are found in dolomites formed by late diagenesis, exhibiting the highest degree of fracturing, resulting in fast responses in fractures and large λ values. The values of the storage ratio ω also vary (the range of most values is from 3.32 × 10−4 to 2.14 × 10−1), with the overall range almost completely filling all the theoretical limits from zero to one. The greatest values of ω are found in dolomites with the largest storage, due to the large number of small fractures, and silica diagenesis probably reduces the matrix storage. The correlations among the parameters show some significant relationships, especially between λ and Km, λ and Sf, ω and Sf, and ω and Sm.

Equations and methodologies of inlet drainage system discharge coefficients: A review

Abstract Accurate determination of grate inlet discharge coefficients is crucial in reducing modeling uncertainties and mitigating urban flooding hazards. This review critically examines the methods, equations, and recommendations for determining the weir/orifice discharge coefficients, based on the inlet parameters and flow conditions. Reviewing previous studies for inlets showed that the discharge coefficient of rectangular inlets under subcritical flow ranges from 0.53 to 0.6 for weirs and from 0.4 to 0.46 for orifices, while in grated circular inlets, it falls between 0.115 and 0.372 for weirs and between 0.349 and 2.038 for orifices. For circular non-grated inlets under subcritical flow, the weir and orifice coefficients are in the range of 0.493–0.587 and 0.159–0.174, respectively. However, the orifice discharge coefficients of grated and non-grated inlets with unknown Froude number range between 0.14–0.39 and 0.677–0.82, respectively. For supercritical flow, the weir and orifice discharge coefficients of grated and non-grated rectangular inlets are 0.03–0.47 and 1.67–2.68, respectively. Previous studies showed that it is recommended to correlate the discharge coefficients with the approaching flow and Froude number under subcritical and supercritical flows, respectively. Yet, additional studies are recommended for a better understanding of the limits and parameters governing the flow transitional stage between weir and orifice and between subcritical and supercritical conditions. Moreover, further research is required to determine the weir and orifice discharge coefficients of circular inlets under supercritical flow as well as the orifice discharge coefficient range of rectangular non-grated inlets under subcritical flow. Finally, it is recommended to increase the road surface roughness to reduce Froude number, and thereby, increase discharge coefficients of street inlets. The aim of this review is to help inlet designers and authorities promote sustainable cities with resilient urban drainage systems and reduce the environmental, economic, health, and social impacts of urban drainage failure.

A combined experimental and computational investigation of an inducer’s characteristics with gas-water two-phase flow

The objective of the paper is to investigate the internal flow characteristics inside the inducer under the gas-water condition using a combination of experiment and numerical simulations. Gas-water mixing is achieved by an annular gas mixing device and visualized by high-speed imaging technology. Meanwhile, the shear stress transport (SST) k- ω model coupled with the VOF model is applied to investigate the gas phase distribution. Numerically simulated inducer energy characteristics and internal gas-phase distribution are in good agreement with experimental data. The results show that the mixed gas-liquid flow inside the inducer exhibits three flow patterns: wavy flow, bubbly flow, and plug flow. For the wavy flow, a series of wavy structures on the blade surface and gas-pocket bubbles near the blade rim are observed. From wavy flow to bubbly flow, uniform bubble streams on the blade surface and spiraling strip bubbles near the edge of the blade are observed. For plug flow, bubble accumulation results in a bullet-shaped plug, and the strip-shaped bubbles near the blade rim are more obvious. In the same axial position of the inducer, the proportion of gas phase is increasing as the flow coefficient increases, thus affecting the inducer performance. The main frequency amplitude of the pressure pulsations gradually rise when the flow pattern changes from wavy to plug flow.

Numerical study on the influence of turbine swirl on exhaust system

This article employed numerical methods to investigate the aerodynamic, thermal, and infrared characteristics of last-stage turbine swirl on a two-dimensional convergent divergent (2D-CD) exhaust system with an afterburner under varying bypass ratios. The research results indicate that the swirl diminishes the thrust coefficient and flow coefficient of the 2D-CD exhaust system with an afterburner. At a bypass ratio of 0.2, the thrust coefficient and flow coefficient decrease by 0.65% and 1.07%, respectively. When the bypass ratio is relatively small, the swirl flow leads to a decrease in the temperature of the afterburner heat shield. Conversely, when the bypass ratio is relatively large, the opposite occurs. The maximum temperature of the heat shield increases by up to 7.2% (bypass ratio = 0.35), while the average temperature decreases by up to 7.1% (bypass ratio = 0.2). The swirl causes an increase in the temperature of the divergent section heat shield, with the most significant deterioration observed at a bypass ratio of 0.25, resulting in a maximum temperature increase in 12.2%. Swirling flow shortens the length of the jet flow, and as the bypass ratio reduces, this attenuation effect becomes more pronounced. When the bypass ratio is 0.2, the length of the core area decreases by 40.3%, and the infrared intensity of the narrow-side jet flow decreases by 12.5%. Overall, on the XOY detection plane, the maximum decrease in infrared intensity is 11.5%, and the maximum increase is 11.7%. On the XOZ detection plane, the maximum decrease in infrared intensity is 15.9%, and the maximum increase is 5.7%.