Dimensionless Model Research Articles

3D simulation estimation and experimental validation of droplet generation in CFD-based flow-focusing microfluidic chips

Abstract Microdroplets generated using microfluidic techniques offer significant advantages over those generated using conventional methods, including high accuracy and excellent monodispersity. However, there remains a paucity of literature regarding the influence of fluid operating conditions and physical properties on droplet generation, specifically in relation to size and frequency, using computational fluid dynamics (CFD) techniques. In this study, we present a simplified microfluidic chip capable of flexibly adjusting the structure and size of the microchannels based on specific requirements. Subsequently, three-dimensional numerical simulations of this chip were conducted using CFD techniques and fitted a dimensionless model to estimate the droplet generation size and frequency through multivariate nonlinear regression methods. The experimental validation results demonstrated a strong correlation between the fitted data and the experimental observations, with size differences not exceeding 8% and good monodispersity, indicated by a coefficient of variation of less than 2.4%. This study provides valuable insights and a reference for future research.

Base joint hysteresis model for reinforced concrete assembly columns with post-pouring area

In response to the problem of uncontrollable grouting quality of traditional grouting sleeves in the connection between prefabricated components, a column base joint with post pouring area connected by grouting sleeves (PCGS) is proposed. Both the sleeve and post pouring area could cause differences in hysteresis characteristics between prefabricated and cast-in-place components. In order to investigate the hysteresis model of PCGS column base joint, the cyclic load tests and finite element parametric analysis of PCGS column base joint were conducted. The theoretical calculation method for load and displacement of PCGS column base joint at yield, peak, and ultimate characteristic points was established based on equivalent rectangular stress and plastic hinge length in joint area. The average ratios of theoretical calculations to test results for load and displacement at the above three characteristic points are 0.997, 0.983, and 0.983, and 1.020, 1.041, and 0.970, respectively, indicating that the theoretical calculation method can accurately predict the strength and deformation of PCGS column base joint. The dimensionless skeleton curve model with double broken lines in the elastic and strengthening stages, and exponential function in descending stage has been established based on the test and simulated results. The degradation behavior of unloading stiffness and bearing capacity was quantitatively described using the regression fitting method, and the hysteresis rule was defined. The established hysteresis model can effectively reflect the strength and stiffness degradation under cyclic loading, which can provide guidance for the elastic-plastic seismic response analysis of PCGS column base joint.

Influence of metal on the far-exploding surface on fragment deformation behavior under contact explosion

Metals exhibit diverse failure behavior under impact loading. In the context of fragment warheads, preformed fragments also undergo fracture and crushing behaviors when subjected to explosive loading, potentially diminishing the terminal effect and damage capability of the warhead. To address this issue, metal disks of varying impedance were applied to the far-exploding surface of the fragments, and their influence on fragment deformation behavior was examined. The experimental results revealed that when metal disks were attached to the far-exploding surface of the fragments, their fracture behavior changed, and the recovered fragments remained intact axially. Additionally, the axial length of the recovered fragments decreased as the impedance of the metal disk on the far-exploding surface increased. To elucidate the underlying mechanism of this experimental phenomenon, the variation in fragment pressure during the propagation process was calculated by employing theories of planar detonation waves and shock wave propagation in the study. The results indicate that when the impedance of the metal disks on the far-exploding surface is higher than that of the fragments, it leads to an increase in internal pressure and the formation of a compression zone within the fragments, thereby preventing fragment fracture. Conversely, lower impedance results in the formation of a tensile effect within the fragments. The theoretical and experimental results were consistent. Finally, based on the dimensional analysis, the dimensionless models were established to predict fragment deformation and internal pressure values influenced by the metal disk on the far-exploding surface.

Simulating the motion of a mechanical arm driven by neural circuit

A simple electromechanical model is constructed in this work to investigate the dynamical behavior of a mechanical arm driven by a light-sensitive neural circuit, simulating the operation of a micromechanical device implanted in the brain under neuronal operation. The physical equation describing the relationship between neural firing and mechanical motion is provided, the dimensionless model is obtained using the scale transformation, and the Hamilton energy of the electromechanical system is calculated based on Helmholtz theorem. It is found that the variation of photocurrent, magnetic field and damping coefficient causes the neuron and mechanical arm to interact with each other to generate a variety of oscillations when the phototube is used as a voltage/current source. Furthermore, it is demonstrated that the conversion of field energy and mechanical energy is another effective method for estimating and controlling the oscillation modes of the electromechanical model. The results explain how a micromassager connected to a neuron processes information from both environment and itself, and provide an insight for the design of implantable neurostimulators to restore brain or muscle function.

A universal drag model for liquid-solid fluidization: Experiment, data-driven modeling, CFD modeling and simulation

Various industrial applications are performed in liquid-solid fluidized beds where drag force plays a significant role in affecting the expansion characteristics of granular-bed, and then determines the mass/heat transfer performance. This study employs dimensionless learning data-driven modeling method, which is derived from the principle of dimensional invariance, to automatically discover the relationship between the drag coefficient and hydraulic dimensionless numbers from the liquid-solid fluidization data. It is found that the Fr number (=ul2/gds) also plays important role in improving the prediction accuracy of drag model except for Re number (=dsulρl/μl). The proposed data-driven modeling method has desired robustness, and the yielded drag model can be applicable to other liquid-solid systems, such as water-polystyrene spheres and water-coal particles, although it is derived from the fluidization of spherical glass beads in rising tap-water. The proposed drag model can also provide good CFD simulation results that agree very well with the experiment data with the relative error less than 5 %.

Experimental and theoretical study on the burning and pulsation behaviors of hydrogen-containing and hydrocarbon jet flames

Hydrogen-containing and hydrocarbon fuels have been widely used in industrial production. Jet fires involving these fuels emerge frequently after leakage or explosion accidents for gas pipelines and processing equipments. To reveal the influencing mechanisms of inclination angle on the pulsation behaviors of jet fires, the burning experiments of hydrogen, syngas, methane and propane jet fires with a nozzle diameter (D) of 15 mm, inclination angles (θ0) of 0°∼90°, fuel flow rates (Qf)of 2.5–40 L/min were conducted. The variations of the global and spatial pulsation frequencies with inclination angle and fuel flow rate are sensitive to the fuel types. Subharmonic pulsation was found at large fuel flow rates (Qf>Qcri). For hydrogen-containing jet flame, a transition from natural pulsation to subharmonic pulsation occurs at a critical inclination angle (θcri). In this case, the transition height where the local pulsation frequency begins to be dominated by subharmonic pulsation, increases with the inclination angle. The local Richardson number (Riy) at the transition height is close to 1. The interaction between the inner and outer vortices increases with the decrease of inclination angle, resulting in decreased natural frequency at the nozzle exit. With the theoretical velocity and flame width at y/D = 2, a unified dimensionless model of natural pulsation frequency was developed, Sty=0.411/Fry0.5, reasonably predicting the natural pulsation frequency of jet flames under different conditions.

Stability analysis of a flocculation model incorporating cell size, time delay, and control

The influence of algal cell size on nutrient absorption, and the time delay in reproduction is paramount in biological terms. Furthermore, the control is necessary during algal flocculation harvesting and sewage treatment. Therefore, we investigated the properties of a single cell algal flocculation model with time delay, size structure and control. First, we introduced a dimensionless model. Then, we analyzed the existence of positive equilibrium states and studied the equilibrium states of the model. Finally, the numerical simulation revealed that the model exhibits backward bifurcation.

Dynamic response mechanisms of thin UHMWPE under high-speed impact

This study systematically explores the dynamic response mechanisms and energy dissipation mechanisms of ultra-high-molecular-weight polyethylene (UHMWPE) fiber laminated plates with thicknesses of 1.1 mm, 2.8 mm, and 5.4 mm under high-speed steel ball impacts through experimental, theoretical analysis, and dimensional analysis. By analyzing the damage mechanisms from experimental results, the main modes of energy absorption were identified, and a relatively accurate predictive model for ballistic limit speed was established. The results show that under high-speed steel ball impacts, the primary failure modes of UHMWPE fiber laminated plates are localized permanent bulging plastic deformation and perforation failure caused by compressive shear. The ballistic limit speeds for UHMWPE with thicknesses of 1.1 mm, 2.8 mm, and 5.4 mm are respectively 233.5 m/s, 415.7 m/s, and 602.9 m/s. The theoretical calculations of the energy model align well with the experimental results, indicating that as the speed increases, the proportion of tensile energy absorption gradually decreases, consistent with the observed phenomena. Near the ballistic limit, there are significant turning points in the level of energy absorption and the height of the rear bulge. The ballistic limit increases linearly with target thickness, and the unit area density energy absorption also increases continuously. Finally, this study established a dimensionless ballistic limit model considering the mechanical properties of fibers and the matrix, which through regression analysis, can accurately describe the ballistic limits of various strengths and types of fiber laminated plates, suitable for predicting the ballistic performance of various composite materials.

Structural strength and fatigue analyses of large-scale underwater compressed hydrogen energy storage accumulator

Underwater compressed hydrogen energy storage (UWCHES) is a potential solution for offshore energy storage. By taking advantage of the hydrostatic pressure of deep seawater, the compressed hydrogen can be isobarically stored in underwater artificial energy storage accumulators. The accumulator should withstand high pressure and large buoyancy and possess reliable anchoring to the seabed. In this study, the structural strength analysis and fatigue life of the large-scale accumulator is conducted employing the finite element method (FEM). The dimensionless stress prediction model and dimensionless fatigue life prediction model are developed through dimensional analysis and multivariate regression analysis. The performance of the accumulator with operating water depth of 100∼300 m, gas storage volume of 1081∼10128 m³, and concrete wall thickness of 0.1∼0.63 m is investigated. The results show that with an operating water depth of 100 m, gas storage capacity of 10,128 m3, and concrete wall thickness of 0.63 m, the maximum compressive stress is 1.43 MPa (yield strength is 60 MPa) and the maximum tensile stress of the accumulator is 2.55 MPa (yield strength is 6 MPa). The design fatigue life is 106 cycles which is larger than the expected service life of 104 cycles. Therefore, the accumulator structure meets the static strength and fatigue life. As the operating water depth increases with a consistent gas storage capacity, a transition in the stress state shifts from primarily tensile stress to predominantly compressive stress. The accuracy of the dimensionless stress prediction model and the dimensionless fatigue life prediction model were verified, with maximum deviations of 10.3 % and 13.7 %, respectively. Furthermore, the anchoring factor of safety of 1.12 is achieved.

Model-based humidity observer for vehicle proton exchange membrane fuel cell based on a new sliding mode observer estimation technique

ABSTRACT The internal water content of the proton exchange membrane fuel cell (PEMFC) stack significantly affects its performance and duration. To achieve optimal humidity level, real-time monitoring of the humidity of the cathode and the anode is crucial for the PEMFC. As far as we know, the relative humidity of the PEMFC can be estimated via an observer based on the measurable output voltage. However, the rapid changes in vehicle operating conditions pose a challenge to the estimation accuracy. Different from the existing sliding mode observers (SMOs), this study pays more attention to the testing noise of voltage measuring sensor. To reduce the noise influence and improve the estimation accuracy, a new sliding mode observer (NSMO) combined with an online Kalman filter is presented based on the dimensionless model of the PEMFC in this study. The applicability of the proposed NSMO in estimating the cathode relative humidity and the anode relative humidity is illustrated by the simulation results. At the same time, comparisons between the NSMO and the online Kalman filter are provided which show a substantially higher estimation accuracy and lower cost for the NSMO. Furthermore, the final results indicate the mean absolute deviations of the cathode and the anode relative humidity for the NSMO are, respectively, reduced to 0.39% and 0.28%.

Correcting the orbits of coexisting solutions via a piezoelectric element in energy harvesting systems

This paper aims to present a novel and complex methodology for realizing high-energy orbits in energy harvesting systems. To achieve this, we have designed a new system structure that consists of elastic elements with variable configuration. In the first part of the work, we identified the characteristics of a potential function and performed a sensitivity analysis depending on ten thousand values of parameters defining the geometry and stiffness of the system. Then, for selected characteristics and based on the dimensionless model, we calculated and compared the energy effectiveness for various identified coexisting solutions and chaotic and periodic motion zones, with identification of transient chaos. In the second part of the work, because of the existence of high- and low-energy orbits, we conducted simulations to investigate the possibility of changing it by an impulse applied directly to the piezoelectric element. We used the Impulse Excitation Diagram supplemented by multicolored probability distribution maps illustrating the possibility of achieving a stable orbit at given numerical values of the impulse amplitude and duration. On the basis of such maps, it was possible to optimally select parameters of the impulse to jump to a high-energy orbit.

Experimental study on the flame trajectory evolution of horizontal jet fires under reduced pressures

Jet fire including process pipeline/tank leakage, oil exploitation industry of tail gas treatment flare or other industrial combustors as a common phenomenon can be found at high altitude areas. This work characterizes the flame trajectory evolution of horizontal jet fires under reduced pressures, which is rarely studied. The experimental results show that the horizontal flame projection distance increases monotonously, but the vertical flame length first increases and afterward decreases with the increase of heat release rate and the decrease of ambient pressure. Meanwhile, flame trajectory length increases significantly and then slowly with increasing heat release rate, but first increases to a maximum value and afterward declines with decreasing ambient pressure. Meanwhile, the turning point of vertical flame length appears earlier than that of flame trajectory length with increasing heat release rate (or jet velocity at source) and decreasing ambient pressure. Then, a mathematical model based on the flame arc hypothesis and a dimensionless model were proposed to describe the flame trajectory length, the momentum-buoyancy length scale Lm=(M0/g′)1/3 was used to normalize the flame trajectory length. The measured flame trajectory length in terms of the nozzle diameter, heat release rate, and ambient pressure was satisfactorily correlated by the proposed models.

Experimental study of the wall particle motion in a screw reactor

Screw reactors are gas/solid systems widely employed in industrial applications. Understanding the local powder mixing within these reactors is crucial, particularly at the reactor wall where wall/solid heat transfer occurs. This study proposes a non-invasive measurement method utilizing optical devices to assess wall particle motion. Two techniques for evaluating the particle motion are compared: a simple visual tracking method and particle image velocimetry. Both methods yield similar results, demonstrating consistent wall particle motion across the tube periphery during experimentation. The influence of operational and geometric parameters has been investigated, revealing that filling degree, powder flowability, and screw geometry significantly impact wall particle motion. Symbolic regression has been employed to derive dimensionless models that effectively predict experimental data. These models can be utilized to forecast wall particle motion, serving as a valuable tool for screw conveyor design.

Implementation and assessment of a model including mixotrophs and the carbonate cycle (Eco3M_MIX-CarbOx v1.0) in a highly dynamic Mediterranean coastal environment (Bay of Marseille, France) – Part 2: Towards a better representation of total alkalinity when modeling the carbonate system and air–sea CO2 fluxes

Abstract. The Bay of Marseille (BoM), located in the northwestern Mediterranean Sea, is affected by various hydrodynamic processes (e.g., Rhône River intrusion and upwelling events) that result in a highly complex local carbonate system. In any complex environment, the use of models is advantageous since it allows us to identify the different environmental forcings, thereby facilitating a better understanding. By combining approaches from two biogeochemical ocean models and improving the formulation of total alkalinity, we develop a more realistic representation of the carbonate system variables at high temporal resolution, which enables us to study air–sea CO2 fluxes and seawater pCO2 variations more reliably. We apply this new formulation to two particular scenarios that are typical for the BoM: (i) summer upwelling and (ii) Rhône River intrusion events. In both scenarios, our model was able to correctly reproduce the observed patterns of pCO2 variability. Summer upwelling events are typically associated with a pCO2 decrease that mainly results from decreasing near-surface temperatures. Furthermore, Rhône River intrusion events are typically associated with a pCO2 decrease, although, in this case, the pCO2 decrease results from a decrease in salinity and an overall increase in total alkalinity. While we were able to correctly represent the daily range of air–sea CO2 fluxes, the present configuration of Eco3M_MIX-CarbOx does not allow us to correctly reproduce the annual cycle of air–sea CO2 fluxes observed in the area. This pattern directly impacts our estimates of the overall yearly air–sea CO2 flux as, even if the model clearly identifies the bay as a CO2 sink, its magnitude was underestimated, which may be an indication of the limitations inherent in dimensionless models for representing air–sea CO2 fluxes.

Dimensionless thermal performance analysis of a closed isothermal compressed air energy storage system with spray-enhanced heat transfer

The isothermal compressed air energy storage (I-CAES) technology boasts the advantages of high theoretical round-trip efficiency and zero carbon emissions. In order to rapidly and efficiently assess the thermodynamic performance of I-CAES, and addressing the limitations of the overly complex thermodynamic model for spray heat exchanged closed-loop I-CAES (CI-CAES), this paper establishes a dimensionless evaluation model related to container size and initial state a*, spray water quantity b*, start or end spraying time c*, and the ratio of liquid level to droplet velocity u*. The expressions for evaluation indicators such as round-trip efficiency, indicated efficiency, compression exergy efficiency, and expansion exergy efficiency are summarized, revealing the impact patterns of dimensionless numbers on the thermodynamic performance of CI-CAES. The results show that the relative difference in the percentage of air enthalpy change calculated using the real gas model versus the ideal gas model during the expansion stage is 88.26 %. The indicated efficiency and round-trip efficiency of CI-CAES simulated by the real gas model were 88.18 % and 60.51 %, respectively, for the design parameters, and the variable condition operation of the hydrodynamic machinery was the main reason for the lower round-trip efficiency. The larger the values of a* and b*, the closer to the isothermal process, and the greater the effect of b* on the performance of the CI-CAES system compared to the two. When b* is 50, the polytropic indices of the compression and expansion stages reach 1.03 and 1.01, respectively. The round-trip, compression exergy efficiency and expansion exergy efficiency all vary parabolically with c*, suggesting that there is an optimal c* that optimizes the system performance. The change in pressure ratio has a greater effect on round-trip efficiency and on the percentage change in air enthalpy during compression and expansion, and u* has a lesser effect on system performance. The results of the research can provide theoretical guidance for the efficient operation of CI-CAES.

Design and development of pilot plant applied to wind and light abandonment power conversion: Electromagnetic heating of solid particles and steam generator

With the rising capacity of renewable energy electricity but incomplete supporting dissipation equipment, this work develops a new charging and discharging device for electromagnetic heating of solid particles to convert electricity from renewable sources into superheated steam, which achieves battery storage efficiency with sufficient safety, terrain-independent and scalable through paralleling. The study reveals that the electro-thermal conversion efficiency of electromagnetically heated iron ore particles increases with particle mass flow rate at different wall temperatures, reaching a maximum of 93.8% at 500 °C. In contrast, the efficiency trend for quartz sand particles is inconsistent, peaking at 68% due to poor thermal conductivity causing inefficiencies at higher mass flow rates. A dimensionless mathematical model (Re-Nu, Re < 10) for both particles is derived from experimental data, offering theoretical guidance for industrialization. Experiments with a shell-and-tube solid particle-packed bed yield continuous production of 35 kg/h, 300 °C superheated steam for 12 min with an 86.4% discharge efficiency and achieve an 81% cycle efficiency, which surpasses compressed air storage(60%), approaches battery and flywheel efficiency(85%). Economic feasibility analysis for a 5MW/5MWH system under two business models demonstrates a short payback period of 2.62 years when providing industrial steam and 6.4 years when used in thermal power plant flexibility transformation. Technological innovations to improve equipment efficiency are critical to the first business mode (selling steam), while grid-determined peak prices are critical to the latter (thermal flexibility retrofits). The study underscores the technical and economic superiority of the proposed devices for utilizing abandoned wind and light, providing a novel solution for carbon reduction and peak shaving in the context of new energy.

Dimensionless analysis-based permeability model of reinforced concrete under tension

Water permeability of reinforced concrete is essential for transportation of ingress ions inside concrete structures. The coupling effect of permeability and loading presents a challenge for the experimental simulation of water-permeate reinforced concrete subjected to tension. This renders the development of the model based on dimensionless analysis, using a series of experimental tests from an innovative experimental system that allows simultaneous measurement of permeability and crack width. The experiments focused on both ordinary concrete and high strength concrete under tension. The relationship between permeability and variables such as deformation, diameter of rebars, tensile load, and crack width under tension was formulated through multiple regression analysis using the testing data. The load to deformation characteristics determines the permeability of the concrete under tension. The proposed model accounts for the influence of continuous loading on permeability, as demonstrated by the robust analysis and proposed yield effective point. The robust analysis demonstrates that the diameter of the rebar, load, and crack width exert minimal influence on the permeability of concrete at lower significance levels. However, permeability variations become pronounced from 0.5 threshold, with significant changes observed between 0.5 and 0.9 thresholds. The findings indicate a differential impact of the variables on the permeability of concrete under tension. The yield-effective points delineate the relationship between the rebar diameter, load, and crack-width on the permeability of concrete with a threshold of 0.5, 0.5, and 0.58, respectively. At a threshold of 0.78, higher permeability will occur in the concrete, attributed to the prevalence of deformation. This deformation highlights the parameters with the most significant influence on the permeability of concrete under tension. The robust analysis and yield effective point derivative are useful parameters to measure concrete permeability and evaluate the behavior of the permeability model under tension.

Thermal runaway and combustion of lithium-ion batteries in engine room fires on oil/electric-powered ships

The thermal characteristics of traditional fuel fires can be altered by the thermal instability of lithium-ion batteries (LIBs) in–oil-electric hybrid ships. The thermal runaway (TR) and combustion of 18,650 LiFePO4 LIBs with 0 %, 50 %, and 100 % states of charge (SOC) in pool fires were studied with different annular n-heptane pools. The goal is to simulate the thermal safety of LIBs in hybrid ships within the thermal environment of pool fires. The flame morphologies resulting from the combustion of the battery and pool fires, temperatures of the battery surface and flame, exhaust characteristics of the battery, heat radiated from the pool fire to the battery, and mass losses were analyzed. The results showed that the risks of thermal runaway and combustion with LIBs were significantly higher in a thermal fire environment. Lithium batteries produce jet fires that increase the width and height of the flame during pool fires. Moreover, the battery with a 0 % SOC doesn’t experience thermal runaway during the fire, but thermal runaway of the battery with a 100 % SOC is more severe than that of the battery with a 50 % SOC, and the maximum rates for their temperature increases are 12.98 °C/s and 7.12 °C/s, respectively. In addition, the energy balance method showed that the pressure relief by the battery safety valve during a fire was not dependent on the SOC. An equivalent network diagram was constructed for the radiative heat transfer between the lithium battery and the pool fire. It is proposed that the total heats required to induce thermal runaway of batteries with the same SOCs are almost the same in different thermal environments, but the energy required for the 50 % SOC battery is greater than that required for the 100 % SOC battery, 10,161 ± 59 J and 9724 ± 43 J, respectively. Moreover, the combustion rates were proportional to the height of the flame during the mixed combustion of a lithium battery jet fire and pool fire. A dimensionless model was developed for the relationship between flame height and mixed combustion rate.

Enhancing resilience in urban utility tunnels power transmission systems: Analysing temperature distribution in near-wall cable fires for risk mitigation

Urban utility tunnels are integral to the underground power transmission systems of cities. Enhancing the understanding of cable fire hazards within these tunnels is pivotal for fostering risk-resilient underground environments. This study delves into the temperature distribution characteristics of near-wall cable fires in urban utility tunnels. Employing a reduced-scale utility tunnel model, a series of fire experiments were conducted, focusing on the safety monitoring of horizontally arranged cables. Cone calorimeter tests were initially performed to ascertain the heat release rate of cable fires. The study meticulously considered cable spatial position parameters, such as cable height and near-wall distance, as dependent variables, and monitored real-time temperature changes within the utility tunnel under various fire scenarios.The findings reveal that the cable’s proximity to the wall significantly influences the fire temperature field. For instance, when a fire near the sidewall (at 1 cm) is compared to one in the middle of the tunnel (at 20 cm), the ceiling maximum temperature is reduced by 38.9 %. The sidewall’s limiting effect diminishes fire energy release, moderates vertical temperature decay, and enhances longitudinal temperature attenuation. The study introduces dimensionless mathematical models that account for the sidewall effect, quantifying the characteristics of fire-induced smoke temperature distribution in utility tunnels, such as ceiling maximum temperature rise, vertical smoke temperature profile, and longitudinal smoke temperature decay. The models’ predicted values closely align with the experimental results.These insights are pivotal for integrating cable numbers and spatial positioning in scenario-based fire prevention and mitigation strategies. The study’s implications extend to the design and operation of urban utility tunnels, emphasizing the need for strategic cable placement and the potential for mathematical models to inform risk mitigation measures. The research contributes to the advancement of sustainable urban development by providing a framework for enhancing the safety and resilience of critical infrastructure against fire hazards.

Modelling the Smoke Flow Characteristics of a Comprehensive Pipe Gallery Fire with Rectangular Section

In this study, a numerical model of the cable cabin of a comprehensive pipe gallery was established to study the smoke flow diffusion behaviour of a comprehensive pipe gallery fire under a rectangular cross-section. The effects of fire source power (Q = 0.5, 1.0, 1.5, 2.0, 2.5, 3.0 MW) and fire source location (D = 10, 20, 40, 50, 60, 80, 100 m) on the smoke flow characteristics—such as smoke layer height and thickness, longitudinal airflow velocity, and ceiling temperature distribution—were analysed, and the corresponding prediction model was fitted. The results show the following: (1) The height of the smoke layer decreases with increasing fire power, and the predictive model of the smoke layer thickness obtained from the fitting is proportional to the smoke mass flow rate and inversely proportional to the aspect ratio of the pipe gallery. (2) Longitudinal air velocity prediction models of D &lt; 50 m and D ≥ 50 m are fitted, and the average error between them and the numerical simulation values is 9.611%. (3) The temperature decay gradient of the smoke decreases gradually with increasing distance from the fire source, while there is a significant temperature difference between the two sides of the fire source. The average relative errors of the dimensionless temperature rise models fitted upstream and downstream of the fire source in the form of ΔTT0=AeBD−XH+C exponentials with respect to the numerical simulations were 11.688% and 7.296%, respectively. The results of the study can provide a reference for smoke flow and fire prevention and control in comprehensive pipe galleries.