Flowing Air Stream Research Articles

АЭРОДИНАМИКА МОДЕЛИ ЖЕЛЕЗНОДОРОЖНОГО ГРУЗОВОГО ВАГОНА ПРИ РАЗНЫХ УГЛАХ АТАКИ ВОЗДУШНОГО ПОТОКА

The problem solution is considered for an airstream flow around a rectangular parallelepiped railway car model. The results of computer modeling in ANSYS CFX software system of air flow aerodynamics at its deviation from the longitudinal axis of the car are given. The k-ε turbulence model is used to close the Navier–Stokes equations averaged by Reynolds. The distribution diagrams of the flow velocities and pressures on the frontal and side surfaces of the vehicle are obtained. The values of aerodynamic drag coefficients of the car depending on the attack angle are determined. It is shown that when the attack angle increases from 0 to 10°, the aerodynamic coefficient changes nonlinearly, and this increase corresponds to the experimental values. The developed numerical modeling technique makes it possible to analyze the airflow around both railways rolling stock and automobiles.

Comprehensive analysis of airflow stream interaction, space utilization and optimization of an aligned configured air-cooled Li-ion battery pack

The spacing in a lithium-ion battery pack is crucial in various aspects; including mechanical stability, heat dissipation, temperature distribution, thermal coupling, and cooling effectiveness. This research aims to enhance the cooling efficiency of a 24 V, 10Ah, 4P7S aligned battery pack by optimizing the distribution of spacing among the battery cells. The parameters examined in this study are the longitudinal pitch (Dx), transverse pitch (Dy), and distance of first row with the side walls (Dw). The Computational Fluid Dynamics (CFD) approach is utilized to compute the flow and temperature fields of the battery thermal management system (BTMS). Thereafter, CFD simulations, in conjunction with the Taguchi approach of Design of Experiments (DOE), is used to determine the optimal parameters. Additionally, an experimental set-up is developed to validate the numerical results with experimental outcomes. Thermal performance evaluation includes examining temperature changes both along and across the airflow direction, temperature variation around the circumference of the cells. The key parameters such as maximum temperature (Tmax), average temperature (Tavg.), maximum temperature differential (∆Tmax), and temperature standard deviation (σT) are also determined. Furthermore, it is assessed that how different distances affect the necessary power (P) and space utilization factor (α) for the airflow. Enlargement of the cooling air vortices within the backflow zone with an increase in Dx is observed to cause a drop in Tmax, Tavg., ∆Tmax, and σT. In addition, as Dy is increased, the values of these parameters fall to a minimum and then begin to rise. Dw also shows a similar impact. Changing Dx from 20.00 mm to 36.00 mm raises inlet pressure, which causes P to increase by 0.57 W. It is determined that the optimal dimensions to maximize the thermal performance of the battery pack in question are (Dy = 24.00, Dx = 36.00, and Dw = 12.00, mm). The numerical results closely matched with the experimental results, with a maximum absolute relative error of 1.48%.

Analysis of the air stream flow parameters generated by the positive pressure ventilator—full scale experiment and CFD simulation

Positioning the positive pressure ventilator in front of the door opening affects the effectiveness of the rescue operation carried out during a fire. An important factor determining the effectiveness of the positive pressure ventilator is also the layout of the rooms within the gas exchange path and the obstacles present there. The purpose of this article is to assess the feasibility of using analyses such as large eddy simulation (LES) to verify the efficiency of mobile fans under simulation conditions, without the need for time-consuming experimentation (also for complex room volumes of buildings). The article presents a comparative analysis to assess the degree of convergence of flow parameters obtained during an experiment (in a multi-story building) and computational fluid dynamics (CFD) simulations. For volumetric flow rate, convergence was achieved at levels ranging from 0.4% (for 5 m) to 11.5% (1 m), and for pressure values, the differences achieved ranged from 0.6% (5 m) to 30.1% (4 m). This paper demonstrates that the LES model can be used to perform CFD simulations in the area of assessing the performance of a positive pressure ventilator. The article also describes a test methodology for determining the flow parameters of an air stream, which can be used to perform numerical simulations.

Using shock generator for the fuel mixing of the extruded single 4-lobe nozzle at supersonic combustion chamber

The importance of the fuel injection configuration on the propulsion efficiency of high-speed vehicles is apparent. In this article, the use of an annular extruded 4-lobe nozzle for the injection of fuel jet in a supersonic combustor of a scramjet engine in the existence of a shock generator is examined. The main aim of this study is to obtain the efficient jet arrangement for efficient fuel mixing inside the engine of hypersonic vehicles. A numerical approach is used to model the supersonic air stream and cross-jet flow with the SST turbulence model. The role of nozzle altitude and internal air jet on the fuel mixing of the hydrogen within the high-speed domain are disclosed. The importance of the horseshoe vortex and counter-rotating vortex on the fuel distribution is also presented. Our results show that the usage of a coaxial jet instead of an annular jet would increase fuel mixing by more than 40% in the combustion chamber.

Experimental studies of the influence of mobile fan positioning parameters on the ability to transport the air stream into the door opening

The article aims to determine the influence of fan positioning parameters, i.e., its distance from a door opening (1–7 m) and the angle of inclination of the impeller axis in relation to the ground (0°–18°) on the amount of air flow pumped through a door opening. The experiment was carried out using a mock-up simulating a door opening, on which a measurement plane was located, without the cubic capacity (building structure) behind the door opening. The volumetric air flow stream was determined based on measuring (at 50 measuring points) the velocity of the air stream blown onto the surface of the door opening mock-up. Four commercial positive pressure ventilators, commonly used in rescue operations, with a power of 0.6–6.3 kW were tested. The tests showed that the value of the air flow stream at the most favourable setting (distance in the range of 3–5 m and the angle of the impeller axis to the ground in the range of 5°–12.2°) is included in the range of 18,304 ± 2460 m3/h to about 45,189 ± 4619 m3/h. Such settings cause the air stream to be aimed at the central area of the door opening. Imprecise mobile fan arrangement may reduce the flow rate from 41 to 76% in relation to the most favourable results.

The effect of the dielectric barrier discharge plasma actuator in the control of non-reactive flow in a non-premixed bluff body burner

Active flow control methods based on dielectric barrier discharge plasma actuators can be used to increase the efficiency of combustion systems. In this study, the influence of the location of plasma actuators on the bluff body in a non-premixed burner on the non-reactive flow field of fuel and oxidizer is investigated numerically. Flow field properties and spatial mixing deficiency (SMD) are calculated to evaluate the plasma actuator's influence on the reactants' mixing inside the burner. The results show that the plasma actuator can influence the recirculation areas and are effective in mixing fuel and oxidizer. The presence of the plasma actuator results in the formation of a vortex, which slows down the movement of the flow and improves the mixing between the fuel and airflow streams resulting in more favorable combustion. The results show that at a higher air velocity (4 m/s), the formation of a plasma zone near the air duct strengthens the external circulation zone (ERZ) in such a way that it surrounds the internal recirculation zone and reduces the value of SMD by an average of 7.89%. While activating the actuator also strengthens the ERZ for a lower air velocity (0.3 m/s), this affects the air inflow, and the flow field becomes dominated by the fuel jet flow. When the diameter of the bluff body is increased, both when the plasma actuator is active or inactive, the ERZ is greatly strengthened, and the flow field is more dominated by the airflow.

Adaptacyjny algorytm regulacji strumienia powietrza

The paper presents an adaptive air stream control algorithm for use in a bioreactor for waste composting. The system controls the streams of air supplied to the six ducts of the bireactor. Bioreactors of this type are characterized by the fact that the porosity of the charge is very heterogeneous throughout the volume. In addition, during the process, the charge is compacted and blockages for the gas flow often occur. The control algorithm should take into account the formation of blockages and attempt to clear them. In situations where unblocking is impossible, it should ensure proper distribution of air flow in other ducts despite the presence of blockages. The overriding goal of this algorithm is to ensure equal air flow streams in all channels, regardless of differences in flow resistance. Since the air circulation in bioreactors is forced by fans with constant capacity, the algorithm should adaptively determine the maximum average value of air streams that is possible to obtain under given conditions and adjust the control system to achieve it. The paper proposes a solution to meet these requirements.

Behavior of Gas Entrainment Inside Viscous Pool Due to Combined Influence of Symmetric Rotational Field and Freestream Flow of Air

Abstract The present investigation elucidates the interfacial characterization caused by the simultaneous effect of a symmetric converging rotational field and continuous air stream flow above the free surface. The converging rotational field is developed by a couple of counter and equal rotating rollers fully immersed inside the viscous liquid medium and their centers are aligned along a horizontal line. Such phenomenon is abundantly encountered in various engineering devices, where the interactions and transfer of mass, momentum, and energy are quite important through gas–liquid interfaces. Behavior of entrainment profile is observed due to the influence of various relevant pertinent parameters, namely, rotational of speed (measured by Ca), submersion depth (b*), the gap between the rollers (2a*), and strength of air stream flow (measured by Reflow). An upper rounded structured interfacial configuration is obtained for all cases of Ca when the rollers are located very close to each other. The length of the entrainment of cusp decreases with the rise of Reflow for the same value of Ca. The value of Cac increases continuously with the increase of Reflow for a particular of 2a* and b*. Bubble ejection from filament tip and subsequent accumulation increases significantly with the rise of Ca for a particular case of Reflow. The cusp tip progressively traverses in upward direction with the continuous increase of gravitational pull for a particular value of Ca and Reflow. Entrainment length progressively grows with the continuous rise of viscous drag for a particular value of Ca and Reflow. Finally, an analytical formulation is proposed to analyze the structure of entrainment and this model reports an excellent match with the numerical findings.

Gaseous Entrainment Dynamics in a Viscous Pool Due to Combined Influence of Asymmetric Rotational Field and Crossflow of Air

Abstract Efforts are made to perform simulations to describe the gaseous entrainment dynamics in a viscous liquid pool due to the combined influence of asymmetric converging rotational field and continuous freestream flow of air. A pair of counter-rotating and equal sized rollers is placed inside the pool along a horizontal line. Gerris is an open-source solver, which is employed to carry out the present computational study. Complex interfacial configurations are illustrated with the influence of relevant input parameters, such as rotation of rollers 1 and 2 (measured by Capillary number, Ca1=Rω1μl/σ and Ca2=Rω2μl/σ, where R=D/2 is roller radius), submersion depth (b*), the gap between the rollers (2a*), and strength of air stream flow (measured by Reynolds number, Reflow=ρgUD/μg). It has been observed that the depth of steady entrainment is reduced at Reflow≠0 compared to Reflow=0 because the hydrodynamic force acts as an opposing force to viscous pumping and rotating inertia. A complete understanding of disintegration of and subsequent accumulation of gaseous bubbles from the cusp tip is characterized in detail. In addition, the influence of viscous drag (specified by Morton number, Mo=gμl4(ρl−ρg)/(ρl2σ3)) and gravitational pull (estimated by Archimedes number, Ar=gD3ρl2/μ2) on the phase contours are also reported. Finally, an analytical formulation is proposed to analyze the structure of entrainment, and this model reports an excellent match with the numerical findings.

Experimental Assessment of Rotary Solid Desiccant Dehumidifier Assisted Hybrid Cooling System

"The prime objective of the present investigation is to assess the performance evaluation of rotary solid desiccant dehumidifier integrated vapor-compression integrated hybrid thermally cooling system by experimental investigation for the transient humid conditions. The experimental test set up is precisely designed and practically fabricated so as to obtain the consistent experimental data during performance testing. The main aim of the experimental investigation is to measure the overall system performance of the rotary solid desiccant assisted hybrid dehumidification and cooling system in terms of COP by measurement at various ambient conditions, air stream flow rates and different regeneration temperatures. The desiccant integrated hybrid thermally cooling system (DAHCS) is primarily the environmental protection technique for indoor comfort cooling purpose of the various residential and commercial building applications. This system also reduces the CFC level in the environment because it minimizes the use of conventional refrigerant. It is found that the rotary solid desiccant dehumidifier assisted hybrid cooling system (DAHCS) is alternate suitable option against vapor compression integrated conventional cooling system in transient humid climates. The desiccant assisted hybrid cooling system (DAHCS) has proven their feasibility and energy saving in the field of built environment. It is concluded that this innovative cooling technology is feasible and demand low energy for comfort cooling. This study is very useful in enhancing opportunities to extend further innovation and core research in different areas of desiccant integrated hybrid thermally cooling system.

Effect of inclined fuel injection in the strut wake region for a hydrogen fueled scramjet combustor

The supersonic airflow and injected fuel stream mixing process is complicated for a scramjet combustor because of little supersonic air resident time and high airflow stream momentum. The direction of fuel injection into a supersonic airflow stream plays a significant role in mixing enhancement with turbulence generation. This study investigates the effect of strut-based parallel (primary) and inclined fuel injection in the strut flame holder wake region. The primary strut with parallel injection is derived from the open literature. The base model strut consists of parallel injection, whereas in the new models, the fuel is injected at an angle of θ for both the upward and downward directions. By computing the Reynolds averaged Navier-Stokes equations, finite-rate eddy dissipation turbulence chemistry, and SST k-ω turbulence models, the mixing and combustion behavior for various fuel injections were investigated. The impact of different fuel injections on the downstream wake region is assessed by evaluating the distribution of H2 and H2O species in the radial and axial directions. The turbulence intensity and turbulent kinetic energy are also considered to evaluate the cross-impact of the air stream and fuel stream for inclined fuel injection. Numerical results found that inclined injection significantly impacts the mixing phenomenon with the development of enriched re-circulation zones in the vicinity of the flame keeper. The mixing and combustion efficiencies performance parameters are evaluated for different fuel injection schemes and found the average increased mixing efficiency of 13% and combustion efficiency of 12%, respectively, for inclined fuel injection. From the analysis of mixing efficiency, it is observed that complete mixing has been found after 235 mm, whereas for inclined injection, the complete mixing happened within a 175 mm distance. The maximum of 75% and 62% combustion efficiency has been observed at a 225 mm and 285 mm distance for inclined and parallel fuel injection, respectively.

Model of Hydrodynamic Friction in the Boundary Layer on an Inclined Flat Surface of an Aircraft

An integral method for solving the problem of longitudinal flow of an inclined flat plate located in a stream of air flow is presented. As a result of the integration of the equations of motion over the thickness of the boundary layer, the two-dimensional problem becomes one-dimensional. The problem was solved numerically in the Mathcad software package. The graphs of the dependence of the thickness of the boundary layer and friction on the longitudinal coordinate at different angles of inclination of the plate are presented. The flow mathematical model can be used to determine the characteristics of two-dimensional boundary layers with arbitrary boundary conditions.

The Stack Effect on the Thermal-Fluid Behaviour of a Solar Collector

The article investigates the thermal behaviour of a solar collector retrofitted with a natural draught unit. The objective of this work is to draw a comparative line between a system that is equipped with a circular vertical channel and the conventional one. The effectiveness of the solar heating system and how to further improve the prevailing system are examined in this study. The flat plate solar collector was used to assess the dynamics of the system. The Hottel–Whillier–Bliss equation was used to obtain the useful heat gain rate. The instantaneous collector efficiency was reduced by 22.84%. The net heat loss encountered with natural draught was augmented by 10.89%. The net pressure drop along the length of the collector was increased when a solar collector related to the circular chimney. The stagnant temperature of the collector with the natural draught was decreased by 3.20%. The heat loss to the surrounding was computed to be 33.94% of the net energy received by a solar collector connected with the circular stack. The Fanning friction factor for airflow was reduced in the system equipped with natural draught. The static pressure was marginally dropped at the inlet, whereas it was steeply increased at the outlet of the solar collector. The static pressure would be the same for both systems at collector length l = 0.84 m. The inference can be deducted from the comparative analysis that the air stream flow behind the collector plate and could provide better prospects for a collector unit equipped with natural draught at the exhaust end of the solar dryer.

Hydrological Season Can Have Unexpectedly Insignificant Influences on the Elevational Patterns of Functional Diversity of Riverine Macroinvertebrates.

Simple SummaryFreshwater ecosystems are increasingly affected by climate dynamics. This study is the first to explore the seasonal effects on the spatial patterns in functional diversity along an elevational gradient. The results showed that the pattern of functional diversity of riverine macroinvertebrates along the elevation gradient was either unimodal or monotonically decreasing. Seasonal changes did not affect the elevational patterns. The findings provide important research and management tools for the temporary effects of river ecosystems.Spatial biodiversity is a key issue in biogeography for the explorations of biological origin and diversification. However, seldom studies have addressed the temporal changes in spatial patterns of biodiversity. We explored the taxonomic and functional diversities of riverine macroinvertebrates in central China, with the elevational gradient, in different seasons in a normal climate year (i.e., no extreme anomalies in the annual precipitation or average annual temperature). The air temperature and streamflow discharge were decreased monotonically with the increase of elevation both in the dry and wet seasons. In addition, the total nitrogen had no significant change with the increase of elevational gradient in the dry season but showed a monotonically decreasing pattern in the wet season. The total phosphorus showed a monotonically decreasing pattern with the elevational gradient in the dry season but had no significant change in the wet season. The spatial pattern of taxonomic diversity of macroinvertebrates along the elevational gradient showed complex patterns, but the functional diversity had either the unimodal or monotonically decreasing pattern. In addition, the functional diversity with the elevational gradient had similar patterns between the dry and wet seasons. Further analysis of the elevational pattern in different seasons is an important basis for understanding the status quo of functional diversity and formulating countermeasures for biodiversity conservation.

Geometric Optimization of Complex Heat Exchangers using Constructal Technique

The application of microchannel heat exchangers for cooling is documented in this study. Numerical optimization is carried out with the goal of minimising the peak wall temperature in the microchannel heat sink modelled with solid and half hollow square micro fins. A high-density heat flux q'' from a microelectronic device was applied at the bottom wall of the microchannel heat sink with circular flow channel embedded in a highly conductive rectangular block aluminium substrate. Single phase water was used as coolant to remove the deposited heat at the internal channel walls and in the internal surfaces of half hollow square fins, while cool air stream flows externally over the vertical fins in a forced convection laminar regime to take away the excess heat on the micro square fins. Computational Fluid Dynamics (CFD) code was employed to descretised and solve the governing equations. The results of numerical optimization showed that the combined microchannels with solid square fins has the highest global thermal conductance than the microchannel with half hollow square fins. The limiting case of a single microchannel heat sink without fins agrees with what is in open literature.

Theoretical and Experimental Studies of Uneven Dust Suction from a Multi-Cyclone Settling Tank in a Two-Stage Air Filter

In this paper, the uneven air stream distribution problem of individual cyclones is studied in the multi-cyclones of intake air filters in special vehicles’ engines. This problem increases in multi-cyclones, in which several dozen cyclones have a common dust trap from which the collected dust is continuously removed by ejection suction. The aim of this study is the recognition of the theoretical and experimental possibility of reducing the streams’ unevenness, which should result in an efficiency increase in multi-cyclone separation. The methods that led to obtaining a relative stream uniformity from the suction of individual cyclones was analyzed. The method for creating equal pressure drops between the suction streams in the channels was used to achieve this goal. For this purpose, the internal structure of the multi-cyclone settler was changed. The multi-cyclone settling tank space was divided by vertical partitions into independent segments. The settling tank segment was then divided with horizontal shelves into suction channels of different heights, which were assigned a specific number of individual cyclones. The suction channels’ height was theoretically selected in terms of the equal resistance to air stream flow through the channels. For this purpose, the multi-cyclone dust settler segment model was developed. The theoretically determined suction channel’s height was verified by performing experimental flow tests in four (A, B, C, D) dust settler variants. Suction streams of satisfactory uniformity from the cyclones of the variant D settling tank were obtained at a level of 5%. In the next stage, experimental tests of the segment cyclones were carried out with dust before and after the division into suction channels of variant D for the settling tank. A significant increase was achieved from 93.73% to 96.08% in the cyclones’ separation efficiency, which were located as far away from the suction stub as possible and led to a reduction in the non-uniformity of cyclone efficiency in the segment. It follows that the multi-cyclone dust settling segment’s internal structure change gave the expected results.

Direct numerical simulation of evaporating droplets based on a sharp-interface algebraic VOF approach

This study presents a sharp-interface algebraic volume-of-fluid (SA-VOF) approach towards direct numerical simulation of evaporating droplets in a finite-volume framework. An interface identification scheme is introduced to determine a sharp layer of interface cells where liquid-vapor phase change occurs. The rate of vaporization is directly computed from the local gradient of the vapor mass fraction at the interface without any tuning parameter in the evaporation model. In addition, a modified compressive differencing scheme is employed to maintain high resolution of the interface. A solver based on the SA-VOF approach is developed and validated by several case studies including the Stefan problem for evaporation in one dimension, evaporation of sessile droplets in the constant contact angle mode, and evaporation of droplets suspended in a flowing air stream. Comparisons between numerical predictions and either analytical solutions or experimental data show that the SA-VOF approach not only computes the evaporation rate with high accuracy but also ensures highly resolved liquid-vapor interface. The solver demonstrates the capability in revealing minute details of the complex characteristics associated with droplet evaporation.

Humidification dehumidification saline water desalination system utilizing high frequency ultrasonic humidifier and solar heated air stream

An experimental investigation on the solar desalination system was conducted according to humidification dehumidification methodology hybrid with hot air stream flow and vapor compression cycle as a condensation unit. A high-frequency ultrasonic atomizer (HFUA) was used as a humidifier which rapidly reaches 100% Relative Humidity. The tests were done during Aug. and Sept. 2020 under the climate of Suez city, Egypt 29.9668°N, 32.5498°E. The effect of high-frequency ultrasound atomizer situation, water height, and hot air stream flow rate on distillate yield were studied. The results illustrated that increasing atomizer number and decreasing water height increases the daily distillate production. The maximum daily freshwater productivity occurred at atomizer number N = 6, rising 38.6% and 115% compared with N = 4 and N = 2, respectively. Furthermore, water height at H = 1 cm is the most efficient with 16% and 28.6% increment compared with H = 2 cm and H = 3 cm, respectively. The optimum hot air stream flow rate ṁa = 0.01156 kg/s with an increment of 55.95%, 31%, 6.48%, 11.3%, and 38.5% compared with 0.0086, 0.01011, 0.013006, 0.0144, and 0.0173 kg/s, flow rates, respectively. The daily production reaches 7.72 kg\\day, the system efficiency 33.84 % and the estimated cost per unit liter is 0.03437 $/L.

Numerical and Experimental Research on Single-Valve and Multi-Valve Resonant Systems

Multiple valves in the pipeline system belong to obvious periodic structure distribution types. When a high-speed airstream flows through the pipeline valve, it produces obvious aero-acoustic and acoustic resonance. Acoustic resonant systems with single and six-pipe valves were investigated to understand the flow and acoustic characteristics using a numerical simulation method and testing method. The strongest acoustic resonance occurred at a specific flow velocity with a corresponding Strouhal number of 0.47 corresponding to the geometric parameters in the paper. Moreover, acoustic resonance occurred in a certain velocity range, rather than increasing with the increase of the velocity of the pipeline. This regular increase provided an important theoretical basis for the prediction of the acoustic resonant and ultimate acoustic load of a single-valve system. When the pipeline was attached with multiple valves and the physical dimension was large, the conventional aero-acoustics calculation results were seriously attenuated at high frequency; the calculation method involving a cut-off frequency in this paper was presented and could be used to explain the excellent agreement of the sound pressure level (SPL) below the cut-off frequency and the poor agreement above the cut-off frequency. A new method involving steady flow and stochastic noise generation and radiation (SNGR) was proposed to obtain better results for the SPL at the middle and high frequencies. The comparison results indicated that the traditional method of Lighthill analogy and unsteady flow could accurately acquire aerodynamic noise below the cut-off frequency, while the new method involving steady flow and SNGR could quickly acquire aerodynamic noise above the cut-off frequency.

Solar desalination unit coupled with a novel humidifier

The solar desalination system is experimentally investigated according to humidification dehumidification methodology (HDH) with hot air stream flow and heat pump as a condensation unit. The effects of high frequency ultrasound atomizer number, water height and hot air stream flow rate on distillate yield are studied. The results illustrated that increasing of atomizer number and decreasing water height increases the daily distillate production. The maximum daily freshwater productivity occurred at six atomizer number with an increase of 38.6% and 115% compared with atomizer number four and two, respectively. Furthermore, water height at 1 cm is the most efficient with an increment of 16% and 28.6% compared with 2 cm and 3 cm, respectively. The optimum hot air stream flow rate is 0.011 kg/s with an increment of 36.88%, 31.07%, 6.48%, 11.72%, 23.52% and 38.60% compared with 0.009, 0.010, 0.013, 0.014, 0.016, and 0.017 kg/s, flow rates, respectively. The air mass flow rate has a significant impact on system performance. The maximum gain output ratio (GOR) of the system is about 1.54. The daily production reaches 7.72 kg∖day, the system energy efficiency is 33.84% and 1.43% exergy efficiency the estimated cost is 0.0112 US$/L.