Inlet Parameters Research Articles

Primary investigation on Ram-Rotor Detonation Engine

The study presents a new type of detonation engine called the Ram-Rotor Detonation Engine (RRDE), which overcomes some of the drawbacks of conventional detonation engines such as pulsed detonation engines, oblique detonation engines, and rotating detonation engines. The RRDE organizes the processes of reactant compression, detonation combustion, and burned gas expansion in a single rotor, allowing it to achieve an ideal detonation cycle under a wide range of inlet Mach numbers, thus significantly improving the total pressure gain of the propulsion system. The feasibility and performance of RRDE are discussed through theoretical analysis and numerical simulations. The theoretical analysis indicates that the performance of the RRDE is mainly related to the inlet velocity, the rotor rim velocity, and the equivalence ratio of reactant. Increasing the inlet velocity leads to a decrease in the total pressure gain of the RRDE. Once the inlet velocity exceeds the critical value, the engine cannot achieve positive total pressure gain. Increasing the rim velocity can improve the total pressure gain and the thermodynamic cycle efficiency of RRDE. Increasing the equivalence ratio can also improve the thermodynamic cycle efficiency and enhance the total pressure gain at lower inlet velocities. While at higher inlet velocities, increasing the equivalence ratio may reduce the total pressure gain. Numerical simulations are also performed to analyze the detailed flow field structure in RRDE and its variations with the inlet parameters. The simulation results demonstrate that the detonation wave can stably stand in the RRDE and can adapt to the change of the inlet equivalence ratio within a certain range. This study provides the preliminary theoretical basis and design reference for the RRDE.

Real-time improvement method of turbo-shaft engine component-level model based on dimensional reduction of residual iterative equation

This paper explores a method to improve the real-time computation performance of turbo-shaft engine component-level model by reducing the dimensionality of residual equations set. For turbo-shaft engine, nozzle typically operates in a subcritical working state, assuming that the gas total temperature and pressure parameters of power turbine inlet are the same, and by assuming the gas flow balance between gas generator outlet and nozzle inlet, the iterative solution of the pressure drop of nozzle can be obtained. Then the pressure ratio of power turbine is naturally obtained, thereby achieving the objective of dimensionality reduction of the residual equations set. The component-level model’s steady-state and transient performance were simulated on a desktop computer with a clock frequency of 2.6 GHz. Simulation results show that, with a 2% margin of error, the steady state computation time for the component-level model was reduced by 54.8%, while the transient performance computation time was reduced by 18.6%. This represents a noticeable improvement in real-time performance. Simulation results on the P2020 embedded processor platform with an 800MHz clock frequency indicate a 22.3% reduction in single-step maximum transient performance computation time of the reduced dimensional model, compared to the original model. This demonstrates the effectiveness of dimensionality reduction of the residual equations set in enhancing the model real-time computation performance.

Investigation of the recompression pathway in the supercritical CO2 Brayton cycle: Cycle modification and thermodynamic study

The recompression process in supercritical CO2 (S-CO2) Brayton cycle is highly energy-intensive, leading to significant temperature rises and complex interactions with internal regeneration and overall cycle performance. This paper aims to investigate the influence of recompression path selection on S-CO2 Brayton cycle and explores opportunities to improve cycle performance by varying the recompression intake position. To actively regulate recompression inlet temperature, two modified layouts based on the conventional recompression S-CO2 Brayton cycle are proposed. Detailed energy and exergy analyses are conducted for these cycles. Optimization is then conducted for modified cycles under different operation conditions to find the optimal recompression path. Thermal efficiency maps with variation of key variables are depicted among cycles to give a comparative evaluation for recompression path selection. The results show that the modified recompression cycles could overtake conventional cycle in thermal efficiency under various certain operation conditions. At split ratio lower than 0.5, further precooling before recompression enhances thermal efficiency. In a case study, thermal efficiency is improved from 39.1 % to 41.7 %. Efficiency of modified cycle becomes less sensitive to main compressor inlet parameters. The modification of three-stage recuperation is effective to eliminate inner pinch point during recuperation and enhance cycle efficiency, with a proper higher recompression inlet temperature. At higher split ratio, shifting recompression path could bring benefits, with a maximum thermal efficiency increasing from 41.6 % to 43.6 % in the case study. Efficiency deterioration could be mitigated by reasonably changing recompression path in off-design operation.

Design and Optimization of Air Inlet in Cuttings Incubator

The microclimate environment can be conveniently controlled with accuracy by plant incubators, in which the cuttings propagation method can efficiently enhance seedling production. To ensure air flow evenly throughout the incubator, the scientific design of the air inlet is crucial. This study utilized a computational fluid dynamics (CFD) model to simulate the airflow patterns in a culture layer under different air inlet conditions. Furthermore, the optimal design parameters were determined by way of response surface methodology (RSM) and the Non-dominated Sorting Genetic Algorithm-II (NSGA-II). Adopting the optimal parameters, a prototype was manufactured, and a cuttings experiment was carried out with apple cuttings in the incubator. The results showed that the optimal air inlet radius is 90 mm, the optimal air inlet height is 188 mm, and the optimal uniform flow plate hole diameter is 13 mm. Meanwhile, the apple cuttings were able to root. Therefore, this incubator with optimal parameters can be used for cuttings. The study provides a methodological and theoretical basis for the future optimizing of air inlet parameters and promoting cuttings rooting.

Energy efficiency analysis of novel combined open absorption multifunctional heat pump and FlashME desalination system with a compressed air dryer

Energy intensive thermal desalination and compressed air-drying processes coupled with low grade heat recovery units can significantly contribute to carbon and energy footprint reduction. In this paper, a novel combined system based on an open absorption multifunctional heat pump and FlashME desalination system with a compressed air dryer is proposed to recover the latent heat from flue gas and efficiently utilize it to drive the desalination process for seawater treatment and supply the compressed dry air. The energy performance of the combined system is analyzed under the effect of various key operational parameters by simulating the validated process model. The results of energy analysis indicate that the novel system can recover the latent waste heat from flue gas with an efficiency of 83.02 % and supply the compressed dry air at low humidity of 1.41 g/kg by operating at a thermal COP of 1.95. Furthermore, the system can efficiently utilize the recovered low-grade heat to produce freshwater at a recovery rate of 23.14 %. The findings of the critical performance analysis show that the drying, and latent heat recovery performance of the coupled system is dependent mainly on the inlet parameters of the spray solution and the flue gas humidity. However, the water recovery of FlashME is totally dependent on heat capacity and the regeneration pressure such that the performance ratio increases from 1.51 to 4.03 by operating with hot seawater of 60–80 °C, when the regeneration pressure is raised up to 53.48 kPa. Moreover, the coupled system configured in parallel double stage can lower 11.43–37.78 % regeneration load along with 54.24 % improvement in distillate productivity when the operating pressure is raised up to 800 kPa and the rise in airflow rate in dryer can decrease the 10.41–52.45 % regeneration load on external heat source.

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.

Research on recompression supercritical CO2 power cycle system considering performance and stability of main compressor

The supercritical carbon dioxide (sCO2) power cycle has good prospects for use in many energy applications. Ensuring the stable operation of the power cycle is an important issue. The inlet condition of the main compressor in the sCO2 recompression cycle is close to the critical point of CO2 and the physical properties of CO2 change drastically near the critical point, so the study of inlet parameter change behavior of the main compressor is of great significance to the stable operation of the equipment and the system. This paper investigates the performance of an sCO2 recompression power cycle system under off-design conditions with different cooling and heating conditions. Unlike previous studies, this paper uses more accurate compressor and heat exchanger models to simulate the system for off-designed performance. A 1-D optimization prediction model of the compressor and a density-based segmented heat exchanger model are introduced to predict the performance changes of the system. The operating conditions, performance, and stability of the compressor under different cooling and heating conditions were compared. The results show that variations in different cooling and heating conditions change the inlet temperature of the compressor, causing the sCO2 compressor to deviate from optimal operation. As the inlet temperature increases, the power consumption of the compressor increases. At an inlet temperature of 305 K, the power is 1.93 MW (main compressor, MC) and 2.17 MW (recompressor, RC). When the inlet temperature increases to 310 K, the power increases by more than 10 %. The largest change in system efficiency is 3.76 % for a change in cooling conditions, and the largest change in compressor speed is 14.23 % (MC) and 7.79 % (RC) for a change in heating conditions, respectively. The operating condition of the main compressor moves far away from the surge line when its inlet temperature increases, which means the operation of the main compressor is more stable in this situation. The results of this paper contribute to the stable operation of the sCO2 recompression cycle.

Visual experimental study on cavitation performance of double-suction centrifugal pump

In this paper, the cavitation test results of double-suction centrifugal pump are further “visualized” and verified by using high-speed photography technology to photograph the development process and flow field of impeller inlet cavitation. By optimizing the impeller inlet parameters, the key geometric factors affecting the cavitation performance of the double suction pump were determined. The experimental results show that by optimizing the inlet parameters of the double-suction pump and combining the visualization test verification of cavitation, on the basis of ensuring the wide and efficient efficiency of the double-suction centrifugal pump, the optimization scheme of the experimental design greatly improves its cavitation performance, and provides a new design idea and reference for guiding the development and design of products with high cavitation performance.

Research on the thermal behavior of medium-temperature phase change materials and factors influencing the thermal performance based on a vertical shell-and-tube latent heat storage system

Medium-and-high temperature latent heat storage systems have been developed to address challenges related to exhaust heat utilization and energy peak regulation in the field of energy engineering. However, there is still a lack of understanding regarding the thermal behavior of medium-and-high temperature phase change materials within heat exchangers and the factors influencing the system's thermal characteristics. Therefore, this study designed and constructed a new medium-temperature (300 °C) latent heat storage system with spiral-finned heat exchanger tubes. It uses 260 kg of medium-temperature phase change material for 68.3 MJ energy storage over 2 h. The system's response to variations in the inlet temperature and flow rate of the heat transfer fluid is investigated using thermocouples and visualization windows and provides recommendations for operating parameters. Results show natural convection as the primary heat transfer mechanism in the charging process, leading to temperature stratification in the tank (the upper has a higher temperature than the lower part). In contrast, heat conduction dominates heat transfer during discharging, resulting in a more uniform temperature distribution in vertical latent heat storage systems. Besides, inlet parameters significantly influence the system. Increasing storage temperature by 20 °C or flow rate by 20 L/min reduces storage time by 33.5 % and 54.0 %, respectively. In contrast, during the exothermic stage, heat conduction dominates with a more uniform temperature distribution. Optimal conditions are found at 280–150 °C, 15 L/min, achieving an input of 84 MJ and output of 50.25 MJ over 200 min, with a cycle efficiency of approximately 59.82 %.

An experimental and numerical investigation of thermofluidic properties on the novel curved microchannel heat sink with slotted section

The current work proposes the development of a novel curved microchannel heat sink by modifying the existing flat microchannel heat sink for enhancing the heat dissipation in the electronic device without significant pressure drop penalty. The inspiration for the curved channel is taken from a NACA airfoil. The microchannel comprises two sections: a curved section and a slotted straight section. Experimental and numerical investigations are performed on the proposed geometry to study the thermofluidic properties for Reynolds number (Re) ranging from 200 to 500 using DI water as working fluid. Fluid flow and heat transfer are analysed by carrying out a full domain numerical simulation in ANSYS Fluent 19.0. The thermofluidic properties of the curved microchannel heat sink (CMCHS) and straight microchannel heat sink (SMCHS) are compared numerically by keeping the geometrical parameters (hydraulic diameter, foot area and fin area) and inlet parameters (inlet velocity and heat flux) identical. The average heat transfer coefficient (havg) of CMCHS is enhanced over SMCHS due to the formation of vorticities in the slotted region owing to the fluid intermixing and boundary layer disruption. The presence of curved section leads to reducing pressure drop penalty pertaining to gravitational effects. Together, the curved section and slotted section enhance the performance factor of CMCHS over SMCHS. The vortices formed increase as the Reynolds number increases, enabling an increase in the heat transfer coefficient. Therefore, the performance factor also increases as the Reynolds number is increased. An enhancement of ≈ 67.6 % in havg is achieved for Re = 500 in CMCHS compared to SMCHS with DI water as the working fluid.

Theoretical Study on Falling Film Fin-Tube Dehumidifier Integrated With an Evaporative Cooler

Abstract The current work presents the theoretical analysis of a falling film fin-tube dehumidifier integrated with an evaporative cooler using CaCl2 as a liquid desiccant. In a fin-tube dehumidifier, the fins are provided outside the tubes to sustain the solution temperature during dehumidification. The evaporative cooler is compiled with a dehumidifier to provide cool air over the fins for maintaining the solution and air temperature. The theoretical model examines the heat and mass transfer between the air and the solution, which are moving in a counterflow direction inside the tubes. The study first presents the validation of the theoretical model with the experimental findings. The maximum disparity between theoretical and experimental results for moisture reduction with solution volume flowrate is found to be ±6.2%, whereas it is discovered to be ±13.8% for moisture reduction with airflow rate. The paper then discusses the air and solution parameters variation along the tube height and the impact of air and solution inlet parameters on system performance. The findings indicate that the variation in outlet air humidity ratio with tube height from 0 to 1 m is observed highest, 0.0264 kg/kg d. a. to 0.0233 kg/kg d. a., for a solution volume flowrate of 12.5 LPM and an airflow rate of 0.05 kg/s. The maximum variation in moisture effectiveness with tube height is observed from 0.0045 to 0.292 at 5 LPM solution volume flowrate and 0.05 kg/s airflow rate.

Metallic Neutral Vapours Diffusion in Electron Cyclotron Resonance Ion Sources: Fluid Dynamics and Particle Tracing Simulations

Resistive oven technique is used to inject vapours of metallic species in electron cyclotron resonance (ECR) plasma traps, where plasma provides step-wise ionization of neutral metals, producing charged ion beams for accelerators. We present a numerical survey of metallic species suitable for oven injection in ECR ion sources, studying neutrals diffusion and deposition under molecular flow regime. These aspects depend on geometry of the evaporation inlet, thermodynamics, and plasma parameters, which strongly impact on ionization and charge-exchange rate, thus on the fraction of reacting neutrals. We considered diffusion of metals with and without plasma. The plasma and its parameters have been modelled considering an established self-consistent particle-in-cell model. Numerical predictions might be relevant to reduce the metal consumption, to increase the overall efficiency, and to improve the plasma ion source performances. As test case, we studied the 134Cs isotope, as one of the alkali metals of interest for the modern nuclear physics.

A Numerical Investigation of Supersonic Combustion Flow Control by Nanosecond-Pulsed Actuations

The efficiency of supersonic combustion is largely dependent on inlet and injection parameters. Additional energy input is required in some off-design conditions, and nanosecond discharge actuation can be a solution. In the present study, a phenomenological model of a nanosecond-pulsed surface dielectric barrier discharge (NS-SDBD) actuator was developed to analyze the combustion enhancement effect for a supersonic combustor with transverse H2 injection. A seven-reaction H2–air combustion model was adopted for the numerical simulation. Dynamic mode decomposition (DMD) was employed to acquire temperature perturbation in spatial and temporal domains. The results show that the actuator provides additional temperature-increment and species transportation through compression waves. The combustion enhancement effect is mainly attributed to the flow perturbation in the shear layer, which promotes the turbulent diffusion of fuel. Given the same power input, the combustion efficiency at the shockwave reflection point is increased by 17.5%, and the flame height is increased by 15.4% at its maximum.

Experimental investigation of heat transfer to carbon dioxide in parallel rectangular channels under supersonic mainstream

Active cooling using carbon dioxide(CO2) is a promising method for supersonic vehicles' combustion chamber, but few studies have considered CO2 heat transfer under supersonic mainstream conditions. In this paper, the double-wall heat transfer effect of CO2 under supersonic mainstream conditions is investigated by using the direct-connection experimental platform. The double-wall consists of an inner liner and a cooling jacket with parallel rectangular channels. The inlet CO2 parameter conditions range for T (Temperature) = 263.3 ∼ 272.5 K, m (Mass flow rate) = 50 ∼ 205.3 g/s, and P (Pressure) = 3.87 ∼ 8.88 MPa. It has been found that the magnitude of CO2 mass flow rate has a very significant effect on the effectiveness of thermal protection. The CO2 active cooling provides effective thermal protection for the inner liner at inlet parameter m = 199.1 ∼ 205.3 g/s, P = 8.69 ∼ 8.88 MPa, and T = 263.3 ∼ 266.8 K. Moreover, the heat transfer reaches thermal equilibrium quickly. However, it is more effective in thermally protecting the inner liner near the CO2 inlet than near the CO2 outlet at the inlet parameters of m = 50 ∼ 88.6 g/s, P = 3.87 ∼ 7.74 MPa, and T = 263.3 ∼ 272.5 K. In addition, there may be a risk of structural burnout near the CO2 outlet.

Performance analysis of a novel combined open absorption heat pump and FlashME seawater desalination system for flue gas heat and water recovery

Thermal desalination processes generally consume a huge amount of thermal energy and industries release a large amount of latent waste heat in flue gas exhausts into the environment. In order to efficiently utilize this waste heat and to improve the energy efficiency of desalination process, this paper presents a novel combined system based on the open cycle absorption heat pump and low-grade thermal energy driven FlashME desalination. The proposed combined system is designed to recover the latent waste heat from flue gas exhausts in a parallel double stage open absorption heat pump which is driven by multiple energy sources and efficiently utilizes the recovered low temperature heat in FlashME for freshwater production. The validated process model of the combined system is developed in Aspen Plus and a parametric assessment is carried out to analyze its energy performance with the impact of various independent operational parameters by using HCOOK-H2O as an absorbent solution. The simulation results of the parametric study show that the combined system is capable of recovering the waste heat with an efficiency of 89.42 % by operating at a thermal performance coefficient of 2.21 and utilizes this heat in the form of hot seawater at 70 °C to drive FlashME desalination process for freshwater production at the performance ratio of 3.05. The critical analysis of the results highlights that the heat recovery performance of the absorption cycle is strongly dependent on the inlet parameters of flue gas and spray solution. In contrast, the water recovery performance of FlashME is dependent on regeneration pressure such that the water recovery rate varies from 9.19 % to 37.17 % with a pressure variation between 23.23 and 51.39 kPa which raises the seawater temperature 60–79 °C before the flashing stage. Furthermore, the system is flexible enough to operate with two heat sources of different temperature levels by adjusting the regeneration load in separate regenerators.

Method of matched sections as a beam-like approach for plate analysis

A new numerical method in application to the plate problem is suggested. It starts from consideration of the rectangular elements, each operating by 6 beam-like parameters: four bending parameters (displacement, angle of rotation, bending moment, transverse force) and two rotation parameters (angle of rotation and twisting moment). So, contrary to the classical FEM approach, the conjugation between the adjacent elements occurs between the adjacent sections rather than in polygon vertexes (nodes), and this gives the name to the method – method of matched sections, MMS. Technically, 6 left-side and 6 lower-side parameters are 12 inlet parameters, while 6 upper-side and right-side parameters are 12 outlet parameters; each element is defined by 24 parameters. Outlet parameters are related to inlet ones by 12 matrix relations, which are derived from the approximate solution of each differential equation (equilibrium, physical, and geometrical equations) of the plate theory. The matrix relation between inlet and outlet parameters is written in a form suitable for applying the transfer matrix method. The numerical examples for the thin and Mindlin plates show the high efficiency and accuracy of the method. In particular, the results for the Mindlin plate for minimal thickness give the same results as the thin plate (no shear locking); the method is insensitive to cases when, for adjacent elements, the ratio of dimensions or ratio of rigidities (elastic constants) differ by several orders of magnitude. The application of the method for the thermal as well as for the vibration problem is considered. The possible extension of the method to any curved geometry is discussed, too.

Study on the heat transfer characteristics of CO2 and liquid desiccant CaCl2 aqueous solution in the gas cooler and evaporator

The heat exchangers are essential components in the CO2 heat pump-driven liquid desiccant dehumidification system since the heat transfer performance of heat exchangers directly affects the energy efficiency of the system. However, the heat transfer characteristics of CO2 and liquid desiccant in the heat exchanger have yet to be fully revealed, resulting in a lack of appropriate strategies to improve the heat transfer performance. To address this issue, numerical gas cooler and evaporator models are developed and verified. The effects of parameters such as the weight concentration of the CaCl2 aqueous solution, the CO2 inlet pressure, mass flow rates, and the length of the heat exchanger on the heat transfer performance are investigated respectively under various operating conditions. Results show that the heat exchange load of the gas cooler can be significantly impacted by various inlet parameters of both fluids. In particular, the increase in the weight concentration from 36 to 54 wt.% deteriorates the heat exchange load by over 15 %. Nevertheless, the heat exchange load of the evaporator is hardly influenced by the weight concentration. This is attributed to a great gap in the two fluids’ heat capacity rates, causing the evaporator to be in the maximum heat transfer state. The sign of the maximum heat transfer state of the heat exchanger is whether the thermal effectiveness is close to 1, which is related to the heat transfer area. Therefore, modifying the heat exchanger length could avoid the thermal effectiveness approaching 1. Results indicate that the appropriate length of the evaporator is 3–4 m under the designed operating conditions.

Numerical study on the gasification and shape evolution of single rod-shaped biomass char particle in a hot CO2/O2/H2O atmosphere

In the industrial systems for CO2 gasification of biomass, a large amount of feedstock is presented as rod-shaped particles at different scales. The evolution of such particles during gasification remains unclear. This work investigated the overall gasification characteristics of single rod-shaped biomass char particle in a hot CO2/O2/H2O atmosphere and the intrinsic link between shape evolution and gasification characteristics. The overall gasification characteristics of the particle are discussed, including the influence of various inlet parameters and geometric parameters. The reaction intensity on the particle surface shows significant non-uniformity, which increases with the particle Reynolds number and oxygen concentration but decreases with increasing inlet temperature. The more the particle shape resembles a rod (aspect ratio ranging from 3:2 to 3:1), the more pronounced the non-uniformity of the surface temperature becomes (increasing by over five times). The intrinsic link between particle reaction properties and shape evolution was discussed using the dynamic mesh method. The shrinkage rate at the end of the particle is 1.73 times faster than that at the middle part. The non-uniformity of the surface temperature decreases by 6 % within 5 s, indicating that as the reaction proceeds, the reaction intensity on the particle surface tends to become more uniform.

Hybrid modeling for the multi-criteria decision making of energy systems: An application for geothermal district heating system

The efficiency analysis technique with output satisficing (EATWOS) is a successful tool for determining the most efficient design for energy systems. Since EATWOS is rationally based on the maximal output throughout the minimal inputs, the weights of input and output values considerably affect the analysis results. Therefore, the impact ratio of each input and output term should be sensitively determined. In this study, the artificial neural network (ANN) modeling was used to determine the weights of the input values due to the quantitative effects of these values, whereas the analytical hierarchic process (AHP) was used for the output values due to qualitative effects. A new hybrid method was formed, embedding the ANN and AHP results into EATWOS. The new hybrid model was then applied to a sample geothermal district heating system for optimization. In this aim, 148 designs were formed throughout the different inlet parameters and evaluated by exergoeconomic and exergoenvironmental analysis to conduct the outputs. For the optimum case, the exergy efficiency was calculated as 20.25 %, whereas the SI was determined as 1.25, with the highest score. 1/r and 1/rb were determined as 0.002337 and 0.001677, respectively. The NPV value was determined as 4.44 million $.

Significance of skin vasodilation for bioheat transfer within transiently heated skin tissue

The current study presents a novel bioheat model for simulating heat transfer in skin tissue. The model, which is based on the Weinbaum–Jiji equation and incorporates the Cattaneo approach for flux in tissue, arteries, and veins, offers an improved representation of thermal dynamics in the skin compared to existing models. Numerical solutions of the model were obtained using the finite element method and were compared to experimental measurements. This study specifically highlights the incorporation of vascular inlet parameters and thermal relaxation effects in the thermal profile, which were not considered in previous models such as the Pennes model. This novel approach provides a more comprehensive understanding of heat transfer in skin tissue and has potential applications in fields such as thermal therapy and wound healing.