Compressed Air Research Articles

Viability of Flax Fiber-Reinforced Salt Cores for Aluminum High-Pressure Die Casting in Experiment and Simulation

AbstractParts with undercuts or hollow sections exploit the maximum lightweight potential due to efficient material usage. However, such geometries are often challenging to produce with ordinary tooling technology, especially in aluminum high-pressure die casting (HPDC). In order to close this gap, this paper investigates flax fiber-reinforced salt made by wet compression molding as a new lost core material that can be removed with water. Three-point bending tests and HPDC experiments characterized the material. The 2D and 3D simulations with aluminum melt and compressible air were carried out in ANSYS Fluent 2023R1. The outlet vent boundary condition is characterized separately to address the geometric features of the outlet vent. Combined with a two-phase flow filling simulation, it allows assessing the actual loads on the lost core material. The simulations show an excellent agreement between the proposed one-dimensional, analytical outlet model and the computational fluid dynamics (CFD) results. The 2D filling simulations are helpful to prove mesh convergence and model simplifications but overestimate the loads. A 3D simulation predicts stress peaks up to 33 MPa for an ingate speed of 64 m/s. Conventional, brittle salt cores with a bending strength of 15 MPa fail under these conditions in the HPDC experiment. In contrast, fiber-reinforced salt cores with bending strengths between 11 and 37 MPa are viable thanks to their toughness, which was demonstrated by a eight to 31 times higher energy absorption than the unreinforced benchmark in the three-point bending tests. With the new robust lost core material, a foundry gains a technology advantage that opens up new markets, e.g., in the mobility sector.

Design of a Thermal Performance Test Equipment for a High-Temperature and High-Pressure Heat Exchanger in an Aero-Engine

For next-generation power systems, particularly aero-gas turbine engines, ultra-light and highly efficient heat exchangers are considered key enabling technologies for realizing advanced cycles. Consequently, the development of efficient and accurate aero-engine heat exchanger test equipment is essential to support future gas turbine heat exchanger advancements. This paper presents the development of a high-pressure and high-temperature (HPHT) heat exchanger test facility designed for aero-engine heat exchangers. The maximum temperature and pressure of the test facility were configured to simulate the conditions of the last-stage compressor of a large civil engine, specifically 1000 K and 5.5 MPa. These conditions were achieved using multiple electric heater systems in conjunction with an air compression system consisting of three turbo compressor units and a reciprocating compressor unit. A commissioning test was conducted using a compact tubular heat exchanger, and the results indicate that the test facility operates stably and that the measured data closely align with the predicted performance of the heat exchanger. A commissioning test of the tubular heat exchanger showed a thermal imbalance of 1.02% between the high-pressure (HP) and low-pressure (LP) lines. This level of imbalance is consistent with the ISO standard uncertainty of ±2.3% for heat dissipation. In addition, CFD simulation results indicated an average deviation of approximately 1.4% in the low-pressure outlet temperature. The close alignment between experimental and CFD results confirms the theoretical reliability of the test bench. The HPHT thermal performance test facility will be expected to serve as a critical test bed for evaluating heat exchangers for current and future gas turbine applications.

Calculation model of enjoyment of dust particles by swirking flow in gas flowes

An analysis of the reasons for the formation of deposits in the flue ducts of aspiration systems was carried out. Problems have been noted in removing deposits with compressed air. The purpose of the work is to solve the problems of aspiration systems and reduce the formation of dust deposits in gas ducts. This is possible due to the swirling of the compressed air flow when purging the gas duct. Despite significant pressure losses when organizing flow swirl, compressed air consumption is reduced by 20–40%. A computational model of the entrainment of dust particles by a swirling flow in gas ducts is presented. To describe the physical model of the movement of a dust particle in a swirling gas flow flowing in a gas duct with a circular cross-section, polar coordinates are used. Dependencies have been deter-mined to determine the value of the average axial velocity of the swirling flow required to move a particle along the gas duct. A diagram of the coordinate axes and forces acting on the particle is presented. The forces acting on the dust particle and its connections with the inner surface of the flue are replaced by the reaction of the flue wall. By decomposing the wall reaction into tangential and normal components, differential equations were obtained that describe the motion of the particle. The dust particle is significantly influenced by the forces of resistance to flow around the gas flow Fμ, the friction force on the wall of the gas duct Ffr, the weight of the particle P, the normal reaction of the wall of the gas duct N. Analysis of the fractional composition of various dusts contained in gases aspirated from the equipment of the metallurgical industry and the production of electrode materials showed that For these dusts, the optimal flow is a weak swirl of intensity W*= 0.5–0.8. This swirling intensity can be achieved by introducing a flow of compressed air when blowing at an angle of 36–48°.

Experimental Characterization of a Bladeless Air Compressor

Abstract The Tesla compressor is an innovative technology that offers a unique approach to fluid compression. Unlike traditional compressors that use rotating blades, bladeless compressors utilize closely spaced disks to create compression. The purpose of this article is to design a prototype Tesla air compressor with optimal design parameters and investigate the performance and loss characteristics based on numerical analysis and experimental demonstration. The prototype model has been numerically investigated at different rotational speeds, and the results have been compared with those obtained in experiments. Computational fluid dynamics (CFD) simulations indicate that the rotor-only efficiency is greater than 90% at very low mass flowrates, while the coupling of the rotor and volute leads to a total-to-static efficiency of approximately 58% (without losses) at 14 g/s. At a nominal mass flow of 4 g/s, the highest total-to-static pressure ratio would be around 1.27. Experimental results indicate leakage losses greatly reduce net mass flow, while pressure ratio values are in good agreement with CFD predictions. During this experiment, a maximum isentropic efficiency of 32.4% is measured. Indeed, the prototype included ventilation and leakage losses, which were not modeled in the CFD analysis. It is remarkable that the compressor does not show any unstable behavior down to zero mass flow (closed valve test), where the CFD and the experiment show consistent pressure ratios. An estimation of the losses from end-wall friction and leakage flow is carried out using numerical simulations at different exit radial clearances. Increasing radial clearance results in an increase in leakage and end-wall power loss, the latter being driven mainly by the axial clearance with the casing, which remained unchanged. To minimize leakage, a Teflon ring has been used as a first measure. Numerical calculations have indicated that the leakage rate is approximately 6 g/s at design speed. A brush seal-type solution can improve the sealing system to reduce leakage.

Quantitative Characterization of Compressed Air Systems

In industrial production plants, leaks in the compressed air system (CAS) lead to significant energy losses. In view of rising global energy costs, increasing the efficiency of such systems represents considerable costcutting potential. When analyzing CASs, it is often not possible to quantify the basic consumption and leakages from the available data. For companies seeking to evaluate potential savings and enhance energy efficiency, it is crucial to quantitatively assess the efficiency of CASs in terms of leakage rate. Determining the quality is typically done at a pressure of 1 bar, which is insufficient due to the volume influence of different compressor-units used in production plants. This work focuses on the algorithmic identification of pressure drop intervals as well as the determination and graphical representation of a quantitative trend visualization for industrial pressure drop intervals over a broad pressure range. For the study, the pressures time series of four production sites were recorded within one year. Shutdown periods were identified from the raw data using four machine-learning (ML) clustering and classification methods. By segmenting the pressure drop intervals, the shutdown periods were parameterized, from which quantitative trend visualization for the pressure drop periods due to compressor shutdown could be calculated and interpreted in the context of a graphical representation. The classification methods were compared as part of this work. With an F1-score of up to 0.99 being reached, only the variance differed among the algorithms. From the temporal observation of the calculated trend visualizations, rapidly falling curves suggest an increasing system leakage.

The Graphene Squeeze-Film Microphone.

Most microphones detect sound-pressure-induced motion of a membrane. In contrast, we introduce a microphone that operates by monitoring sound-pressure-induced modulation of the air compressibility. By driving a graphene membrane at resonance, the gas, that is trapped in a squeeze-film beneath it, is compressed at high frequency. Since the gas-film stiffness depends on the air pressure, the resonance frequency of the graphene is modulated by variations in sound pressure. We demonstrate that this squeeze-film microphone principle can be used to detect sound and music by tracking the membrane's resonance frequency using a phase-locked loop. The squeeze-film microphone potentially offers advantages like increased dynamic range, lower susceptibility to pressure-induced failure and vibration-induced noise over conventional devices. Moreover, microphones might become much smaller, as demonstrated in this work with one that operates using a circular graphene membrane with an area that is more than 1000 times smaller than that of MEMS microphones.

Isobaric compressed air energy storage system: Water compensating cycle or CO2 compensating cycle?

Isobaric operation of air storage can remove the throttling losses existing in isochoric reservoir, making full use of the storage volume and lowering system construction cost. The water cycle and CO2 cycle are two of the most commonly configurations to stabilize the pressure in the air storage unit. The choice between the two cycles depends on whether the technical complexity and costs are justified by performance gains. This paper mainly focuses on developing the MAP design, a kindly selection diagram plotting the better value of performance indicators between the two systems, to determine the more favorable compensating cycle in the constant storage operation of the compressed air. The analysis results indicate that higher air storage pressure increases the system efficiency. The levelized cost of storage is provided with a valley value when the air storage pressure is at 6.6 MPa for the CO2 cycle and 14 MPa for the water cycle. The optimized systems can share a comparative efficiency of 68.04 % and 68.07 %, and the levelized cost of storage is 0.8237 ¥/kWh for the CO2 cycle and 0.7869 ¥/kWh for the water cycle. The water is suggested to be the compensating fluid for the isobaric system when the water machine efficiency is higher than 0.85 or else opting for CO2 proves to be a more economically viable choice.

Optimization operation strategy of wind–pumped storage integrated system participation in spot market considering dual uncertainties

Abstract With the gradual increase in the penetration rate of renewable energy, the multifunctional role of pumped storage is becoming increasingly prominent, and the joint operation of “renewable energy + pumped storage” is a current research hotspot. However, during the joint system operation, there are dual risks from internal (renewable energy output) and external (market prices) factors, which significantly impact the system’s overall revenue. Therefore, an analysis is conducted around the operational mechanism of the “wind power–pumped storage” joint operation, and the uncertain factors faced during the system’s operation are identified. Second, an optimization model for wind power–pumped storage under deterministic scenarios is constructed, employing robust optimization theory and information gap decision theory to describe the uncertainty of electricity prices and wind power, thus forming a hybrid of the information gap decision theory and the robust optimization model for wind power–pumped storage. Finally, the results show that: (1) The total revenue of the model proposed in the paper has increased by 2.36% compared to the robust optimization model and by 9.04% compared to the deterministic model, significantly enhancing the model’s robustness and risk resistance capabilities. (2) From the perspective of the economic feasibility of different energy storage system configurations, the wind plant equipped with pumped storage has the highest economic feasibility, with an internal rate of return of 9.8% and net present value of 872 million Chinese Yuan, which is higher than that of compressed air energy storage and electrochemical energy storage systems. (3) Decision makers can set the risk deviation coefficient and the uncertainty budget according to their risk preferences, thereby changing the robustness of the model for differentiated decision making. However, an increase in the uncertainty budget coefficient will cause the total revenue of the joint operation system first to increase and then decrease, with the maximum revenue achievable within the range of 500–625; the total revenue reaches its maximum when the risk deviation coefficient is between 0.1 and 0.125.

Underground compressed air energy storage (CAES) in naturally fractured depleted oil reservoir: Influence of Fracture

In the last decade, the sources of clean energy supply to meet human needs have been given much attention by researchers worldwide. Compressed air storage in underground formations is an excellent way to balance energy production and consumption. During off-peak hours, with the consumption of excess electrical energy, the air is temporarily stored at high pressure in the desired environment. The stored compressed air produces recovered electrical power during the needed hours and peak energy consumption. Compressed air energy storage in underground structures, including depleted hydrocarbon reservoirs, due to having a suitable storage capacity for air and because their geological characteristics have already been well identified, is one of the storage methods. In order to underground storage of compressed air in aquifers and salt caverns, research have been carried out, but so far, studies have yet to be carried out regarding the storage of compressed air in depleted natural fractured oil reservoirs. This study simulated the storage of compressed air in a naturally fractured depleted oil reservoir, the effect of fracture on the rate of oxidation reactions, air dissolution and air diffusion in the oil and water phases. Also, for the first time, an examination of the fracture properties, including porosity, permeability, and fracture spacing on the amount of air recovery during CAES, was numerically simulated. Significantly Increasing the fracture porosity and permeability improves the air recovery and leads to a 19% and 16% respectively increase in the air recovery factor. In the fractured reservoir, increasing the fracture porosity has the most significant effect on reducing the air recovery factor and reducing the fracture spacing has the most negligible effect on the air recovery. Finally, the results of this study showed that due to the consumption and loss of air in the fractured reservoir compared to the conventional reservoir, the air recovery factor in the fractured reservoirs is less than the conventional reservoirs.

A feedback linearization sliding mode decoupling and fuzzy anti-surge compensation based coordinated control approach for PEMFC air supply system

With the application of proton exchange membrane fuel cell (PEMFC) in the field of transportation and energy, the requirements for air flow and pressure tracking performance, efficiency and stability of PEMFC air supply system become higher and higher. To improve PEMFC cathode air flow and pressure control performance under load variation and avoid surge of air compressor, a novel feedback linearization sliding mode decoupling and fuzzy anti-surge compensation based coordinated control approach is proposed. Firstly, optimal references of oxygen excess ratio (OER) and cathode air pressure under different load are calculated based on net output power of PEMFC system analysis. Then, an extended state observer is designed to estimate the cathode air pressure and flow in real time, a feedback linearization sliding mode based decoupling controller is designed to enhance OER and air pressure tracking control performance and robustness. Considering on the operating trajectory and surge line of air compressor, a fuzzy logic based anti-surge compensator is designed to prevent air compressor from surge by compensating both air flow and pressure simultaneously. The proposed control approach is implemented in PEMFC air supply control experiments and the results demonstrates its effectiveness.

Enhancing Bulb Turbine Performance Assessing Air Injection for Vibration Mitigation and Hydrofoil Cavitation

Small hydro technology is playing a crucial role in advancing sustainable, clean energy policies as part of the global hydro development strategy. Its contribution to social and economic development is becoming more prominent, particularly in ensuring electricity access for rural communities and supporting industrial expansion. The main causes of bulb turbine failures under high operating conditions are frequently attributed to variations in pressure in the draft tubes, which are aggravated when a spinning vortex rope is formed under load operation. Different fluid injection techniques, namely compressed air and water jet injection, address these issues and reduce the negative results of cavitation. The investigation covers the flow visualization on the suction side of a single hydrofoil utilizing a cavitation tunnel and a bulb turbine. This study assesses the effectiveness of compressed air injection in reducing vibration generated by cavitation in bulb turbines. Positive results of the experimental studies suggest a decrease in noise and vibration by air injection that prevents oscillations of the vortex rope. This research also considers how the hydrofoil design of bulb runner blades influences flow characteristics. Hence, it provides knowledge on cavitation structures in diverse cavitation numbers. Different studies that compare the original and modified hydrofoil designs reveal remarkable improvements that may be due to changes in the key parameters of the hydrofoil, such as later cavitation initiation and reduced intensity. To obtain the optimal output of a bulb turbine by considering air injection for vibration reduction and hydrofoil design changes to limit the negative effect of cavitation, the Reynolds number and cavitation number are to be defined. This multidisciplinary approach possesses enormous potential to increase the reliability and efficiency of bulb turbines in challenging operating conditions.

Generation of broadband airborne ultrasound using an Harmonic Acoustic Pneumatic Source

This paper presents a new type of airborne transducer for generating broadband ultrasound with a high Sound Pressure Level (SPL). The concept is based on the Harmonic Acoustic Pneumatic Source (HAPS) that uses pressurized air in conjunction with a flow chopper made up of a rotating cage with slots connected to a specific exhaust. The fundamental frequency depends on the number of slots and the rotation speed of the cage. An analytical model of the HAPS coupled with a numerical model of the exhaust is used to predict the radiated acoustic pressure and to estimate the influence of dimensional parameters on pressure level generated by the source. Experiments are conducted with two cages: one with one slot in order to generate pulses periodically and one with 122 slots to generate periodic sound. The level of sound pressure is measured as a function of distance (0.004 to 0.5 m), the cage rotation (up to 11 krpm) and directivity (0 to 90°). For the fundamental frequency at 22 kHz, the maximum SPL of 150 dB (632 Pa rms) is /measured at 0.004 m, and decreases to 122 dB (35 Pa rms) at 0.5 m. At 0.5 m, the second and third harmonics can generate a SPL equal or greater than 115 dB above 22 kHz and up to 66 kHz. Discrepancies between the experiments results and numerical model are observed in terms of SPL, directivity and in-axis pressure.

Sustainable production of Pleurotus sajor-caju mushrooms and biocomposites using brewer’s spent and agro-industrial residues

Brazil is one of the world’s largest beer producers and also a major food producer. These activities generate a large amount of residues which, if disposed of inappropriately, can have adverse effects on the environment. The objective of this research was to evaluate the potential of using these residues for both mushroom cultivation (traditional use) and the production of mycelium-based composites (innovative use). Mushroom production (Pleurotus sajor-caju) was conducted using only brewer’s spent grains (fresh and dried) and also mixed with banana leaves (1:1) or peach palm leaves (1:1), which are residues widely available in the northern region of Santa Catarina, Brazil. The productivity of mushrooms cultivated using fresh and dried brewer’s spent grains did not exhibit a statistically significant difference, indicating that this residue can be utilized shortly after its generation in the industrial process, thereby reducing costs associated with production. Combining brewer’s spent grains with banana or peach palm leaves resulted in enhanced mushroom production (0.41 and 0.38 g day−1, respectively) compared to using the leaves as a sole substrate. The mushrooms produced contain sugars and a minimal sodium content, and are considered a source of phosphorus. In addition, no toxic elements (Hg and Pb) were present. The mycelium-based composites produced using the residual substrate (after the mushroom harvest) exhibited better mechanical properties (compressive strength = 0.04 MPa, density = 242 kg m−3, and low humidity sorption) than those produced using fresh substrate. The results demonstrate the synergistic effect of combining the two approaches under investigation. The use of brewer´s spent enhance the mushroom productivity and the residual substrate enhance the mechanical properties of mycelium-based composites. The compressive strength, density, and air humidity sorption properties are essential for determining the potential applications of mycelium-based composites. The use of brewer’s spent grains mixed with banana leaves demonstrated significant promise for mushroom production and subsequent application in the development of mycelium-based composites. These sequential approaches contribute to waste valorization and the rational utilization of natural resources, as the mycelium-based composites are considered for substitution of synthetic materials, thereby promoting sustainability for future generations.

Recent Patents on Long Distance Pneumatic Conveying Technology

Background: Pneumatic conveying is the use of air flow energy to transport granular materials in the direction of airflow in a closed pipeline, which involves the disadvantages of low conveying efficiency and easy deposition of particles. Objective: It is necessary to develop pneumatic conveying devices to reduce particle deposition, promote particles to enter the flow field again to accelerate, and achieve the effect of extending the pneumatic conveying distance. Method: The anti-settling device re-accelerates the particles so that the particles return to the flow field, which effectively reduces the probability of settlement blockage of material particles during transportation. The pneumatic conveying pressurized separator uses a pot-shaped housing to generate an internal rotating flow field to screen particles, and the light dust adheres to the filter, reducing the possibility of pipeline dust explosion. Results: The anti-settling device can quickly replace the anti-settlement block according to the parameters of the conveying pipeline, which can effectively reduce the probability of settlement blockage of material particles during transportation. The pressurized separator can use the air compressor to cooperate with the return air pipe to effectively remove the dust in the pneumatic conveying pipe and carry out secondary pressurized transportation of the materials in the pneumatic conveying pipe, which improves the safety of pneumatic conveying. Conclusion: The above technology improves the efficiency of pneumatic conveying and gas utilization, enhances the speed of particle conveying, reduces particle settlement and collision, extends the distance of pneumatic conveying, and ensures the safety of pneumatic conveying and the feasibility of industrial applications.

Study on start-up characteristics of single piston free piston linear generator for small-scale compressed air energy storage system

This study presents a new idea of applying single piston free piston linear generator (FPLG) to small-scale compressed air energy storage (CAES) system. Firstly, a single piston FPLG prototype for CAES is built. Then, the thermodynamic, motion and output characteristics of FPLG during start-up process are studied based on the experimental data. The results show that the start-up process of single piston FPLG can be divided into three stages, and the order of achieving a steady state is movement and output > in-cylinder pressure > the in-cylinder temperature. The in-cylinder temperature increases in a spiral pattern, and the temperature difference between adjacent cycles at the same state point decreases. In the 0th cycle, when the free piston assembly (FPA) moves from top dead center (TDC) and bottom dead center (BDC), the peak current and power output are greater than the other cycles. The peak current and power output when FPA moves from TDC to BDC are greater than those when FPA moves from BDC to TDC. The maximum current and power output can reach 0.8 A and 62.25 W. At the beginning of the expansion stage, as the intake duration (tin) increases, the in-cylinder pressure increases first and then decreases. As the intake pressure (pin) increases, the in-cylinder pressure continues to increase. In addition, the in-cylinder temperature of working chamber A (TA) is lower than in-cylinder temperature of working chamber B (TB), and the temperature difference between TA and TB can reach 12.4 K. At higher pin condition, the intake point cannot be too close to the two ends and tin cannot be too long. At lower pin condition, the intake point cannot be too close to both ends and tin cannot be too short to ensure the system starts. The purpose of this paper is to provide valuable insights and guidance for the practical application of small-scale CAES system.

Proposal design and thermodynamic optimization of an afterburning-type isothermal compressed air energy storage system integrated with molten salt thermal storage

The isothermal compressed air energy storage is a potential technique for large-scale energy storage. In this study, the molten salt thermal storage is integrated with the afterburning-type isothermal compressed air energy storage system, which uses liquid piston compression technique, to enhance the thermal performances. Thermodynamic models of the hybrid energy storage system were developed, and the genetic algorithm was used to optimize multiple parameters to enhance the energy efficiency. Four operation modes, i.e., the high, medium-high, medium-low, and the low output power modes were proposed, to enhance the operational flexibility of the hybrid energy storage system. When the system operates in the operation mode of medium-low output power, a portion of afterburning heat is stored in the molten salt and used in the operation mode of low output power. Results show that the roundtrip efficiency of high, medium-high, medium-low, and the low output power modes are 63.57 %, 59.33 %, 57.13 %, and 83.28 %, respectively. Exergy analysis was carried out to quantify the irreversibilities of key components. In the three modes of operation with afterburning, the combustion chamber has the highest portion of exergy loss, and in the operation mode without afterburning, the exergy loss of heat exchangers is higher than that of expanders.

Investigating the thermal performance of a pipe-encapsulated movable PCM wall and its impact on reducing indoor heat gain during summer

The utilization of phase change materials (PCM) in building envelopes is considered to be an effective technology for reducing energy consumption during building operations. In this study, a novel approach is presented for integrating PCM into walls by encapsulating it using pipes, allowing for its mobility through the use of compressed air. Four experimentally validated thermal models, pipe-encapsulated movable PCM (PEM-PCM) wall (Model 1), wall with PCM fixed to the exterior (Model 2), wall with PCM fixed to the interior (Model 3), and wall without PCM (Model 4), were proposed to compare their energy efficiency in summer. Different upper threshold limits (Ttr,up) and lower threshold limits (Ttr,low) were employed to explore the impact of various threshold combinations control strategies on the thermal performance of the wall. The results show that the most effective operating scheme is Ttr,up of 27 °C and Ttr,low of 25 °C. In terms of long-term operation, cumulative summer indoor heat gain of Model 1 is 10.65 %, 10.85 % and 11.4% lower than that of Model 2,3 and 4. Notably, September demonstrates the greatest potential for energy savings, with Model 1 reducing the monthly cumulative indoor heat gain by 54.12% compared to Model 4.

Isolator shape transition impact on hypersonic internal waverider intake flow distortion

This paper examines the impact of scramjet isolator shape transition on hypersonic internal waverider (IWR) intake. The IWR intake is designed using the osculating axisymmetric flows and streamline-tracing methods. The new Internal Conical Flow “M” basic flowfield is utilized to provide the flow information for the design method. The intake is equipped with three isolators: one with a constant cross section and two with variable cross sections with circular and rectangular exits. The entrance shape and area of the three isolators are fixed to the intake throat shape and area. The exit area of the three isolators is maintained as the entrance one. Numerical computations of three-dimensional configurations reveal that the isolators with variable cross section shapes demonstrate a higher uniformity index than those with constant cross section shape. Thus, the isolator shape transition has decreased the flow distortion of the hypersonic IWR intake system. The three isolators exhibit varied wall pressure distribution depending on the isolator cross section shape, and the total pressure recovery ratios at the three isolators' exit planes are similar. The wall pressure distributions and key performance parameters at the intake throat section, including total pressure recovery, compression ratio, and Mach number, remained consistent across the first part of the intakes. Therefore, changing the cross section shape of the isolator while keeping the area constant could enhance the flow uniformity of compressed air without negatively impacting the intake system's performance. This allows a separate shape selection of the IWR intake throat and the scramjet combustor entrance to fulfill their special requirements.

The performance analysis of a compressed air energy storage (CAES) for peak moving with cooling, Heating, and power production

This study focuses on modeling and optimizing a multifaceted geothermal-based energy production system within the context of Denmark. The primary objectives revolve around enhancing system efficiency and reducing operational costs. The system under investigation comprises geothermal components, an organic Rankine cycle, a compressed air energy storage facility, and an absorption chiller. The organic Rankine cycle operates using refrigerants R123 and ammonia, effectively converting thermal energy into electricity and thermal energy for various applications. Optimization was carried out employing the Response Surface Method in tandem with Design-Expert software, facilitating the fine-tuning of objective functions. Two key objectives were selected: Exergy Round Trip Efficiency and cost rate, aimed at improving technical performance and curbing economic expenditure. A range of design variables were considered for optimization, including turbine and pump inlet temperatures, geothermal mass flow rate, turbine and pump efficiencies, compressor and gas turbine efficiency, inlet pressure to the compressed air energy storage tank, and evaporator pinch point temperature. The system reached an impressive exergy efficiency peak of 77.98%, accompanied by a modest cost rate of 5.48 $/h. The costliest components in the system were the compressed air energy storage unit, followed closely by organic Rankine cycle 1 and organic Rankine cycle 2. In contemplating the practical implementation of this innovative energy system, ten cities in Denmark underwent rigorous analysis, accounting for technical and economic factors. Subsequent assessments identified Aarhus as the optimal location to initiate the system. The environmental results showed that by producing 13981.9 megawatts of electricity annually in Arhus City, it is possible to help reduce CO2 emissions by 2853.2 tons of CO2/year and avoid environmental costs of 68455.3 $/year. The environmental assessment also highlighted the potential for substantial green space expansion, estimating an additional 13 hectares of green areas in the city of Aarhus, Denmark.

Design player robot badminton-based microcontroller

Robots are one of the technologies that is currently advancing quickly. Generally speaking, a robot's movement is similar to that of an automobile; it can only move forward, backward, left, and right. Because the movement is controlled by these movements, it is thought that the robot's movement is extremely restricted to the left and right directions. solely with the front wheels. As a result, a robot was developed in this study that can control sliding motions to the left and right utilizing omniwheels on its front and back wheels. Badminton is a sport involving rackets that is played by two people or two opposing pairs. Robotic badminton players are employed as a substitute for human trainers in the training process, particularly for service and drive motions. With the use of a wireless joystick, the robot's ATMega 8535 microprocessor controls both the robot's direction of motion and the movement of its racket. Using a double acting pneumatic cylinder that requires 7 bar of air pressure, the robot service arm uses the compressor's air pressure. The average time it takes for the racket to strike the ball at 7 bar of wind pressure is 00:5.2 seconds. The time it takes for the ball to fall onto the racket in the absence of wind pressure is 00:28 seconds on average. A difference value of 00:22.7 seconds is acquired, and this value will be utilized as the programming reference delay. The robot encounters a slope with an average angle change of 7º when moving forward, an average angle change of 10º when moving backward, an average angle change of 5.2º when moving right, and an average angle change of 3º when moving left. The uneven field surface causes the robot to move at a slope, which modifies the speed of the motor on the wheels