Supply Pressure Research Articles

A novel recyclable surface ion-imprinted graphene aerogels for high selective adsorption of lithium in salt lake brine

To mitigate the growing pressure of lithium resource supply and requirement, the exploration of abundant lithium from salt lake brine has emerged as a novel avenue for lithium resource acquisition. Surface ion imprinting technology with specific recognition could achieve selective lithium adsorption. However, existing Li+-imprinted adsorption materials exhibit poor adsorption performance and difficult recovery. To address these issues, the novel recyclable Li+-imprinted graphene aerogels were synthesized by using graphene oxide as the skeleton material, and thiourea dioxide as the reducing agent, assisted by DMF and NH3·H2O. The imprinted aerogels demonstrate excellent structural stability (bearing 10000 times of its weight), superior adsorption capacity (31.66 mg g−1), high selectivity and good regeneration performance (91.0% after six cycles). The selection factors for Li+ over Na+, K+ and Mg2+ reach 10.00, 5.71 and 4.00, respectively. This is attributed to the strong metal coordination interreaction between 2-Hydroxymethyl-12-crown-4 and Li+, thereby specifically recognizing and adsorbing Li+. This research offers a fresh material for the enrichment and recovery of lithium resources in salt lake brine.

Effects of Recess Depth and Orifice Diameter on Pneumatic Hammer Instability in Hydrostatic Thrust Bearings: Analysis and Experimental Validation

Abstract Hydrostatic thrust bearings (HTBs) are required in various turbomachinery systems due to their substantial load capacity and superior rotor axial positioning capabilities, which minimize friction and heat generation. However, when lubricated with compressible fluids, these bearings can experience pneumatic hammer instability especially if the recess volume is significant. This study aims to establish design guidelines and experimentally validate the performance of hydrostatic thrust bearings, with a focus on predicting and mitigating pneumatic hammer instability. The research includes an investigation into the static load characteristics of these bearings when operated with air as the lubricant. The analysis in this paper covers the effects of varying supply pressures, recess depths, and orifice diameters on pneumatic hammer instability, as well as on the load capacity, stiffness, and damping coefficients of the bearings. To validate these findings, experiments are conducted using two test bearings with differing recess depths and orifice diameters. The results from both predictive models and experimental data consistently show that a shallow recess depth is effective in preventing pneumatic hammer instability without notably diminishing the bearing load capacity. Nonetheless, modifying the orifice diameter to control pneumatic hammer instability requires careful design consideration, as it might lead to decreased load capacity and stiffness. This research addresses the challenge of preventing pneumatic hammer instability in hydrostatic thrust bearings through a combined approach of numerical analysis and experimental testing. It contributes significantly to the field by offering practical design recommendations for optimizing recess depth and orifice diameter. These guidelines aim to eliminate pneumatic hammer instability while preserving critical performance aspects of hydrostatic thrust bearings, such as load capacity and stiffness.

Analysis of the Influencing Factors of Aerostatic Bearings on Pneumatic Hammering

In this study, in order to reveal the influence mechanism of bearing parameters on pneumatic hammering, an aerostatic bearing with a multi-orifice-type restrictor is analyzed. Firstly, the flow field is investigated, and the vortex-induced excitation is discussed in both the frequency and time domains. Then, the frequency-related displacement impedance is analyzed, and the effects of vortex-induced excitation on pneumatic hammering are discussed. Experiments are also conducted for verification. Moreover, the influence of damping on pneumatic hammering is identified. The results show that with larger damping, the risk of pneumatic hammering can be reduced. Finally, the impacts of design parameters on the damping are discussed in detail using an approximate model. Design optimization is considered to achieve the maximum damping, i.e., the minimum risk of pneumatic hammering. The results show that both the air supply pressure and the pocket volume should be minimized. The analysis process provides a reference for the design of bearings to reduce pneumatic hammering.

Experimental study on absorption and desorption behavior of a novel metal hydride reactor for stationary hydrogen storage applications

Metal hydrides have captured significant attention for hydrogen storage because of their high energy density and safety. However, the performance of these systems is largely influenced by the design of the storage reactor. In this perspective, a novel compact, lightweight, and effective multi tube MH reactor was designed, fabricated, and experimentally tested. The absorption and desorption behavior of the newly developed Ti0.9Zr0.1Mn1.46V0.45Fe0.09 alloy using the proposed MH reactor for hydrogen storage applications was analysed. At 30 bar supply pressure, the MH reactor absorbed 164.3 g (1.58 wt.%) of hydrogen in 894 s and delivered specific energy at an average rate of 94.7 W/kgMH. Further, the reactor released 153.6 g (1.48 wt.%) of hydrogen in 2246 s, when the desorption temperature was set at 50 °C. Moreover, the parametric study revealed that by raising the supply pressure from 10 bar to 20 bar and 30 bar, the stored capacity was improved by 11 % and 18.9 %, respectively, whereas the absorption time was drastically reduced by 43 % and 61.5 %, respectively. Furthermore, the fabricated reactor achieved gravimetric and volumetric storage densities of 0.75 % and 20.6 kg/m3 of H2. Also, the MH reactor achieved a maximum hydrogen storage efficiency of 82.3 %. Finally, the comparative results indicated that the MH reactor studied in this work demonstrated a faster hydrogen release rate compared to other medium to large capacity MH reactors reported in the literature.

Effect of cutting fluid supply conditions on tool loads during continuous and interrupted orthogonal cutting

AbstractIn metalworking, cutting fluids play an important role by reducing heat and friction during machining, extending tool life, and improving surface finish. Although the positive effects of cutting fluid have been confirmed in many studies, the relevant cutting fluid parameters such as nozzle cross-section area and supply pressure, as well as their influence on the thermo-mechanical loads of the cutting tool, have been insufficiently investigated. This study investigates the effects of cutting fluid supply conditions on tool loads during continuous and interrupted orthogonal cutting processes. The research specifically addresses the impact of nozzle geometry and fluid jet orientation on the thermo-mechanical loads on the cutting tool, which have been underexplored in previous studies. A prototype tool holder, designed and additively manufactured for this purpose, allows for variations in nozzle geometry and jet orientation. Experiments were conducted under varying cutting parameters, nozzle geometries, and fluid pressures, with tool temperature being monitored through an embedded thermocouple. The results show that nozzle geometry significantly affects chip shape, which directly affects cooling efficiency and, consequently, tool temperature. The study also uses an inversely calibrated analytical model to analyze the tool temperature distribution, which shows that the highest temperatures occur in the tool-chip contact area, while temperatures outside this area decrease rapidly. In addition, the percentage of heat conducted into the tool decreases with increasing Péclet number, which is consistent in both continuous and interrupted cutting scenarios. These findings provide a deeper understanding of how cutting fluid nozzle design affects tool performance and establish a foundation for model-based temperature analysis in machining processes.

COMPARISON OF THE EFFECTS OF STANDARD NOZZLES AND EXTENSION TUBES ON THE EROSION OF PMMA USING PULSATING WATER JET TECHNOLOGY

The study of bone cement disintegration is important for advancing orthopedic and trauma surgery outcomes. Bone cement, commonly used in joint replacement procedures, plays a vital role in fixation implants. However, the long-term stability and integrity of bone cement are critical for the success of these procedures. This study focuses on the use of ultrasonic pulsating water jet technology for the selective removal of bone cement, aiming to provide a precise and efficient method for revision surgeries. The disintegration efficiency is measured in terms of depth, width and volume of the disintegrated bone cement as a result of variations in the nozzle geometry, supply pressure and traverse speed. Two different nozzle types, the standard nozzle insert and nozzle with an extension tube of 100 mm having a diameter of 0.3 mm, are used. Two supply pressure levels were taken as 10 and 20 MPa with five levels of traverse speeds as 0.5, 1, 1.5, 2 and 2.5 mm/s. The results showed an increased disintegration efficiency for all experimental conditions using an extension tube nozzle as compared to a standard nozzle (20 – 25% in terms of disintegration volume). Also, the disintegration efficiency increased with higher pressure level values (8.2 mm3 and 4.85 mm3 for p = 20 and 10 MPa, respectively) and lower traverse speed values. The results showed a promising direction in terms of the utilization of an ultrasonic pulsating jet with a modified nozzle type for higher bone cement disintegration efficiency.

Parameter Analysis of Anion Exchange Membrane Water Electrolysis System by Numerical Simulation

Anion exchange membrane electrolysis, which combines the advantages of both alkaline electrolysis and proton-exchange membrane electrolysis, is a promising technology to reduce the cost of hydrogen production. The present work focused on the study of the electrochemical phenomena of AEM electrolysis and the investigation of the key factors of the AEM hydrogen production system. The numerical model is established according to electrochemical reactions, polarization phenomena, and the power consumption of the balance of plant components of the system. The effects of operation parameters, including the temperature and hydrogen pressure of the electrolyzer, electrolyte concentration, and hydrogen supply pressure on the energy efficiency are studied. The basic electrochemical phenomena of AEM water electrolysis cells are analyzed by simulations of reversible potential and activation, and ohmic and concentration polarizations. The results reveal that increasing the operating temperature and hydrogen production pressure of the AEM electrolyzer has positive effects on the system’s efficiency. By conducting an optimization analysis of the electrolyzer temperature—which uses the heat energy generated by the electrochemical reaction of the electrolyzer to minimize the power consumption of the electrolyte pump and heater—the AEM system with an electrolyzer operating at 328 K and 30 bar can deliver hydrogen of pressure up to 200 bar under an energy efficiency of 56.4%.

Research on Hydraulic Characteristics of Water Leakage Phenomenon of Waterproof Hammer Air Valve in Water Supply Pressure Pipeline Based on Sustainable Utilization of Water Resources in Irrigation Areas

To investigate the causes of water leakage in the waterproof hammer air valve and its impact on sustainable water resource management, the DN100 waterproof hammer air valve was taken as the research object. By using the overset grid solution method of ANSYS Fluent 2021 R1 software, the flow field simulation of the waterproof hammer air valve was carried out. The transient action during the ascent phase of the key structural component floating ball, and the velocity and pressure distribution of the flow field inside the air valve are analyzed. The results showed that by giving different inlet flow velocities, the normal flow velocity range for the floating ball to float up was below 35 m/s and above 50 m/s. When the inlet flow velocity was between 35 m/s and 50 m/s, the growth rate of the pressure difference above and below the floating ball increased from 1.48% to 5.79% and then decreased to 0.4%. The floating ball would not be able to float up due to excessive outlet pressure above, which would cause the DN100 waterproof hammer air valve to leak water and fail to provide water hammer protection. When the inlet flow rate is 5 m/s, the velocity and pressure inside the valve body increase with time during the upward movement of the floating ball inside the waterproof hammer air valve and tend to stabilize at 400 ms. Through the generated pressure and velocity cloud maps, it can be observed that the location of maximum pressure is at the bottom of the buoy, directly below the floating ball, and at the narrow channels on both sides of the outflow domain. The location of the maximum velocity is at the small inlet of the bottom of the buoy. When the inlet speed of the valve is constant, a large amount of water flow is blocked by the floating ball, reducing the flow velocity and forming partial backflow below the floating ball, with an obvious vortex phenomenon. A small portion of the water flow passes through the air valve at a high velocity from both ends of the channel, and the water flow below the floating ball is in an extremely unstable state under the impact of high-speed water flow, resulting in a large gradient of water flow velocity passing through the valve. The research results not only help to improve the operational efficiency of water resource management systems but also reduce unnecessary water resource waste, thereby supporting the goal of sustainable water resource management.

A Thermal Model for a Hybrid Gas Bearing System in Oil-Free Turbochargers

Abstract With little drag friction, gas bearings operate at high rotor speed and high temperature and thus enable long operating life along with material damping for mechanical energy dissipation. However, most computational tools for modeling gas bearings are not accessible to bearing manufacturers or potential end-users, and the models are restricted to specific geometries and operating conditions or are missing important features, thus limiting their utility. This paper presents the thermal energy transport in a hybrid gas bearing (HGB) for oil-free turbochargers (TCs) with integrated heat and fluid flow models to produce a comprehensive thermohydrodynamic analysis predictive tool and to design and evaluate air-lubricated gas bearings by predictions and experiments. An efficient algorithm couples the solution of the Reynolds equations and the thermal energy transport equations in the film between the rotor and a pad of the hybrid gas bearing and updates the temperature-dependent viscosity and film thicknesses during the iterative process. The balance of the bulk-flow thermal energy transport is that the summation of drag power losses plus heat convection into the film equals to the thermal energy advected by the film. The predictions show that the film temperature varies along circumferential and axial directions by following the balance of the energy flows and shows high film temperatures corresponding to the small film thicknesses and thus large film pressures. The predicted result also shows that the peak temperature of the film occurs at the exit side of the film near the trailing edge of each pad. Thermocouples installed axially at the leading and trailing edges of each pad measure temperature of the film to validate the thermal module. The test repeats and averaged for each rotor speed from 2 krpm to 22 krpm at intervals of 2 krpm, for supply pressure varying along 25 psi to 100 psi, and predicted film temperature matches well with the measured one. The parameters of interest in this analysis include the gas supply condition, bearing configuration, and the gas properties at high altitudes and high rotation speeds. The parametric study results show that the density and kinematic viscosity are the most dominant properties of the gas lubrication for the film temperature.

Numerical modelling and analysis for radial error motion of 5-DOF aerostatic-bearing spindles under the unbalanced electromagnetic force

In the realm of ultra-precision machining, the radial error motion of the aerostatic-bearing spindle directly impacts the quality of the workpiece. However, there remains a gap in understanding the underlying mechanisms governing the radial error motion. In this study, a numerical solution method for radial error motion of 5-DOF aerostatic-bearing spindles under the unbalanced electromagnetic force is proposed. The physical model is presented globally considering the governing equation of air film, balance equation of airflow, and motion equation of rotor. The effects of the amplitude of unbalanced electromagnetic force, number of motor pole pairs, supply pressure, and rotational speed on the radial error motion under the unbalanced electromagnetic force are characterized. Additionally, a measurement system is devised to assess the radial error motion of aerostatic-bearing spindles. The congruence between the experimental and simulated outcomes validates the proposed method. The radial error motion can be diminished by minimizing the amplitude of unbalanced electromagnetic force, the number of motor pole pairs, and rotational speed or increasing the supply pressure. Besides, it is found that the number of motor poles is mapped to that of lobes of radial error motion. This study provides practical guidance for the design of aerostatic-bearing spindles with desired radial error motion.

Design and analyses of an AB5 - metal hydride based canister for hydrogen compressor application

The reversible hydrogen storage nature of metal hydride (MH) is widely accepted for the development of MH based energy devices like energy storage, hydrogen compressors, etc. For efficient working of such devices, the appropriate thermal management of canister is very important i.e. extraction and supply of heat during hydrogenation and dehydrogenation, respectively. The accumulation of heat reduces the hydrogen storage capacity as well as detoriarates the reaction rates because of increase in MH temperature. Therefore, to optimise the MH heat transfer, in the present work, a helical coil is introduced within the MH Canister (MHC) to circulate the heat transfer fluid in addition to an external cooling jacket. The purpose of using helical coil is to get more surface contact with MH because of the poor thermal conductivity of MH. The performance analyses have been carried out through a 3-D Finite Volume Approach employed with La0.9Ce0.1Ni5. The analyses include the influence of coefficient of heat transfer, pressure, and temperature on the designed canister as well as the compressor performance. Initially, the numerical model is validated with experimental results available in the literature and observed in good match. Later, the performance of MHC is predicted for different operating conditions which results in the estimated storage capacity of hydrogen is about 1.48wt% at 25bar and 298K. In addition, it is observed that at an elevated supply pressure, the reaction rates increased as well as the rise in MHC temperature increased due to exothermic heat. Later, the MHC is tested for the application as hydrogen compressor which results in the compression ratio of 10.8 with a discharge pressure of 270bar at 140°C providing ~20% efficiency.

Metadata schema for virtual building models in digital twins: VB schema implemented in GPT-based applications

A virtual building model (VBM) is a virtual entity that represents the physical behavior of a target building mathematically within a digital twin environment. The creation and synchronization of a VBM are achieved by utilizing various interrelated virtual sub-models, including behavior, correction, and distance models. To achieve continuous digital twinning, it is essential to manage the VBM with virtual sub-models. However, these metadata schemas have limitations in describing VBMs representing operational building behaviors within the concept of building digital twins (DTs). Therefore, this study proposes a novel metadata schema, termed the virtual building model metadata schema (VB schema), to represent and manage VBMs in DT-built environments. The VB schema is established according to the mathematical and semantic ontology of the in-situ modeling and calibration approach for constructing and correcting virtual models during building operations, and it is linked to physical entities, data, and applications within DTs. Specifically, it involves: (1) determining classes for operational data and virtual models; (2) establishing relationships for interactions between model and data entities, between model classes, between model and physical entities, and between model and applications; (3) defining properties for each class of models; and (4) extending into the exiting metadata schema of Brick. To demonstrate the proposed VB schema, a virtual model describing supply pressure behaviors in a central heating system was developed and represented using the VB schema for DT-enabled building operations. Additionally, the VB schema was utilized for implementing generative pre-trained transformer (GPT)-based DT applications, which highlights its benefits in enhancing ontology comprehension of DTs in the context of VBMs, improving autonomous problem-solving capabilities in real building systems, and providing better interpretation of application results compared to cases where only the Brick schema was used. The VB schema is expected to enable continuous and autonomous in-situ management of VBMs for intelligent building services within the DT.

Static Characteristics of Hybrid Water-Lubricated Herringbone Groove Journal Bearing

Abstract The hydrodynamic herringbone groove journal bearing (HGJB) performs exceptionally well at high speeds but is limited by a low load-carrying capacity, largely due to the lubrication characteristics of water. To address this issue, a hybrid water-lubricated HGJB is proposed in this study. A lubrication model for the high-speed hybrid water-lubricated HGJB is developed, taking into account turbulence, thermal effects, and tilt. A comparative analysis of the static characteristics is conducted between the hybrid HGJB and both the hydrodynamic HGJB and the hybrid plain journal bearing (PJB). The results show that the proposed hybrid water-lubricated HGJB offers significantly greater load-carrying capacity than the conventional hydrodynamic HGJB, particularly during start-up or at low speeds. For example, when the bearing operates at 1000 rpm with an eccentricity ratio of 0.5, the load-carrying capacity of the water-lubricated hybrid HGJB under a supply pressure of 1.6 MPa reaches 650 N, compared to just 261 N for the water-lubricated hydrodynamic HGJB. Additionally, the hybrid water-lubricated HGJB demonstrates a higher flowrate and lower temperature rise than the traditional hybrid PJB, thanks to the improved pumping effect of the herringbone grooves at high speeds.

Fuel Ignition in HTP Hybrid Rockets at Very Low Mass Fluxes: Challenges and Pulsed Preheating Techniques Using Palladium-Coated Catalysts

In a worldwide scenario which sees an increasing number of small satellite launches, novel mission concepts may be unlocked providing the spacecrafts with the very precise and rapid maneuvering capability that electric thrusters cannot guarantee. In this context, chemical thrusters appear to be a possible solution. This work aimed to experimentally study and solve the problem of ignition for 10 N hybrid rockets based on hydrogen peroxide. Firstly, the study analyzed the performance of a monopropellant engine capable of functioning as a hybrid injection system. In particular, the effects of the liquid mass injected, the initial temperature, and the supply pressure on the pulsed engine performance were experimentally investigated. The injected mass showed a greater impact on the performance with respect to the starting chamber temperature and injection pressure. This thruster also showed a good potential for space applications. In the second part of the work, the objective was to find an ignition procedure that reduced propellant consumption and eliminated the need for a glow plug. This is important because the electrical power consumption in real applications significantly affects other subsystems and is undesirable for chemical engines. Different ignition procedures were tested to emphasize their respective advantages and disadvantages, and the findings indicated that the concept of pulsed preheating is feasible with only a small amount of propellant consumption, while substantially decreasing the ignition duration from approximately 45 min to a maximum of just 3 min. Finally, similar ignition procedures were adopted using different fuels. The results showed that PVC and ABS, under the same operating conditions, ignite more easily than HDPE, which requires an oxidizer consumption approximately double that of the other two fuels. Considerations about the effect of chamber pressure and oxidizer mass flow rate on engine ignition were also included.

‘Taming’ a Wicked Problem: Selective Problematisation of Issues of Urban Water Supply in Mumbai

The lack of universal urban water access in the cities in the global south is a wicked problem. Using the case of Mumbai, this paper illustrates how consistently this wicked problem was chiselled and selectively problematised to turn it into a tame problem – a problem of water shortages at the city level. The chiselling included neglecting the essential aspects of urban water supply, such as supply coverage, pressure and leakages, which define the quality of urban water service received by citizens. Through chiselling and selective problematisation, the paper illustrates how the problem of providing universal urban water access in Mumbai was ignored for decades and the issues of water shortages were emphasised alone to justify and prioritise the development of dams.

Energy-efficient and reliable coordinated scheduling for water distribution systems: enhancing hydraulic conditions and water quality

ABSTRACT Multi-objective operation optimization of water distribution systems (WDSs) in large metropolitan areas is essential; however, it is complex and time-consuming. Effective and reliable scheduling of WDSs can significantly enhance the efficiency and reliability of urban water resources management, which requires further research. This paper develops an optimization method combining genetic algorithm and multiple criteria analysis that coordinates energy conservation, hydraulic condition improvement, and water age optimization in WDSs. Results showed that the optimal scheduling method could achieve a 23.0, 16.7, and 2.5% decrease in energy consumption, and water supply volume with unsatisfied pressure, and average water age, respectively. To achieve optimal results, this study indicated that it is crucial to properly allocate water supply volume and pressure across multiple drinking water treatment plants. This finding provides important guidance for water utilities in scheduling. Furthermore, the emergency scenario analysis shows that the newly proposed method can significantly enhance the social and economic sustainability of WDSs through the coordinated optimization of energy consumption, hydraulic conditions, and water age.

Experimental study on the influence of flexible structure and gas supply method on the characteristics of aerostatic tilting-pad bearing

Purpose This paper aims to propose novel flexible structure-supported tilting-pad aerostatic bearings and to improve operational stability and vibration reduction of aerostatic bearings. Design/methodology/approach The authors established an aerostatic bearing-rotor test rig and designed two aerostatic tilting-pad bearings with different flexible support structure and an ordinary aerostatic tilting-pad bearing and then examined their effects in dynamic performance to assess the vibration reduction performance of different flexible structures. Furthermore, the authors proposed three gas supply methods and conducted experiments to study the influence of gas supply methods in the performance of bearings. Findings The experimental results show that among the three structures, the double-layer flexible structure-supported tilting-pad bearing demonstrates outstanding vibration damping performance and it significantly enhances the operational stability of the bearing-rotor system. Furthermore, the experimental results indicate that the gas supply method has a significant impact on the performance of the aerostatic bearing. There is a certain pressure difference between the gas supply pressure for the loading pads and that for the nonloading pads, which is advantageous for increasing the operational stability and reducing system vibration. Originality/value The authors designed novel flexible aerostatic tilting-pad journal bearing structures, which can enhance the operational stability and reduce vibrations of the bearing. Additionally, this article proposes an air supply method advantageous for increasing the stability of the bearing and reducing system vibrations.

Quantitative analysis of hydrogen leakage flow measurement and calculation in the on-board hydrogen system pipelines

The mass flow rate of hydrogen leakage directly affects hydrogen diffusion and concentration distribution. In this paper, a test platform was constructed to measure mass flow rates during hydrogen leakage in the supply pipelines of the on-board hydrogen system. Hydrogen leakage tests were conducted under two different conditions. Mass flow rates were measured for tube fittings with various loosening angles and hydrogen supply pressures. The data were then fitted to extrapolate mass flow rates of hydrogen leakage beyond the tested conditions. Additionally, mass flow rates were measured for hydrogen supply pipelines with small holes of different shapes and sizes. The effects of pipeline size, hydrogen supply pressure, hole shape, and size on the hydrogen leakage mass flow rate were analyzed. Hydrogen leakage flow coefficients were corrected, and the accuracy of three calculation methods for hydrogen leakage flow was compared and analyzed based on the test results. The results provide a foundation for future numerical simulation models of hydrogen leakage diffusion.

Comparative performance assessment of different halide composites in sorption cooling system: A dynamic approach

The adsorption technique presents a promising approach for cooling, heat storage, and gas storage. This study focuses on the viability of adsorption in cooling applications, specifically utilizing various halide salts in conjunction with thermal energy, highlighting its potential as an energy-efficient solution for modern energy demands. A dynamic numerical model is developed and used to study the performance of transverse finned reactor-based adsorption cooling system (ACS) with different halide composite salts. The simulations are carried out at different supply pressures ranging from 3.55 bar to 7.28 bar corresponding to saturation pressure of ammonia at an evaporator temperature ranging from −5 ℃ to 15 ℃ during adsorption. The desorption process is simulated at different regeneration temperatures with a required desorption pressure of 17.28 bar corresponding to saturation pressure at condenser operating temperature of 40 ℃. The average cooling power produced in first 60 min of system operation at an evaporator temperature of −5 ℃ is 4.89 W, 207 W, 206 W and 925 W with the use of BaCl2, CaCl2, SrCl2 and MnCl2 composites respectively. The theoretical maximum coefficient of performance (COP) obtained are 0.31, 0.365, 0.308 and 0.552 with BaCl2, CaCl2, MnCl2 and SrCl2 respectively. The cooling power (CP) is increasing with increase in evaporator temperature. The shortest adsorption completion time is observed at 15 ℃ of evaporator temperature with all metal halides used. The lowest adsorption time is observed with MnCl2 composite salt and highest with BaCl2 composite salt. The regeneration time of all composite salt beds is decreasing with increase in regeneration temperature.

Study on bearsing capacity and rigidity of surface throttling bearing

Abstract Based on the lubrication principle and Reynolds theory, the influence of the pressure field and structural parameters on the bearing characteristics of the surface throttle bearing is analyzed and studied by using the finite difference method. The results show that the surface throttling bearing has obvious static bearing characteristics when the shaft is not rotating; The dynamic pressure effect of oil wedge load can be seen obviously when the shaft rotates. With the increase of radius gap h0, the bearing capacity and rigidity will decrease significantly. The increase of oil supply pressure will reduce bearing capacity and rigidity. With the increase of length-diameter ratio L ¯ , the rigidity will be improved.