Throttle Valve Research Articles

Study on operation performance and application potential of the piston-type thermally-driven pump

To eliminate the high-quality energy consumption of the existing thermally-driven pump and then make it replace the mechanical pump, the piston-type thermally-driven pump with a similar structure to the linear compressor was proposed and studied in the paper. The coupling mechanism of working fluid flow and element dimension was analysed based on the force analysis of the piston assembly. In experimental data analysis, the variation of working fluid condition is used to determine the pump operation stroke. The experimental result shows variation tendencies of the vapor-phase fluid pressure and flow rate are greatly affected by its compressibility. The throttle valve has a major effect on the liquid-phase fluid pressure and flow rate besides the vapor-phase fluid flow rate. And the pump operation period decreases by 0.05 s ∼ 0.1 s as the vapor-phase fluid pressure and the throttle valve opening change under the testing condition. Meanwhile, the correlation mechanism of the action force, displacement and velocity of the piston assembly was analysed through a theoretical simulation. It can be discovered that the piston assembly velocity increases by 7.1 %∼12.6 % and the pump operation cycle decreases by 1.9 %∼6.8 % with increasing vapor-phase fluid pressure. In addition, the improvement direction of the pump structure was proposed based on a comparison between the experimental research and the theoretical analysis. Compared with the mechanical pump, the simulating result shows the thermally-driven pump can in theory reduce the relative power consumption by about 82 %. Finally, an alternative strategy was presented for substituting the mechanical pump with the piston-type thermally-driven pump in the absorption and ejector refrigeration systems, to verify its application potential in the industrial field.

Design and Structural Optimization of Electrically Controlled Throttle Valve Core for Stratified Injection

In order to solve the problems of poor regulation of throttling pressure drop and excessive viscous friction in electrically controlled throttle valves in stratified injection, a new valve core structure that can efficiently regulate pressure drop and reduce viscous friction is designed. An effective valve core simulation model is established, and the model is divided into grids for fluid dynamics simulation. The pressure drop and shear rate of three commonly used valve and throttle structures are compared comprehensively based on the simulation results. The optimal circular arc flow channel structure is selected, and the influence of the length of the circular arc structure on the shear rate is simulated. Compared with 20mm, 25mm and 30mm, the best effect was obtained when the valve joint length is 30mm.The experimental results show that the average viscosity of the optimized valve core is less than 11%, which reduces the viscosity loss.which provided theoretical support for the optimization of layered injection tool.

Sensor fault‐tolerant control for an internal combustion engine

SummaryThis research presents the design of a fault‐tolerant system based on a dual extended Kalman filter (DEKF) and a bank of two high‐gain observers to ensure the continuous operation of an internal combustion engine (ICE) despite total and partial faults in the mass airflow (MAF) sensor, temperature sensor, and pressure sensor. The DEKF aims to estimate the air mass flow rate () through the throttle valve. The DEKF uses the temperature and pressure measured in the intake manifold to accurately estimate the (), a failure in any of both sensors will not allow the correct functioning of the DEKF. Therefore, a bank of two high‐gain observers is proposed to estimate the pressure and temperature from only one measure. Observer 1 estimates the temperature and pressure from the pressure, and Observer 2 uses the temperature for estimating pressure and temperature. Hence, if the temperature or pressure sensors fail, the estimated temperature or pressure will replace the ill‐measure signal. The results show the effectiveness of the proposed fault‐tolerant system in the case of one sensor or multiple sensor faults.

Testing of Regulating and Non-Regulating Hydraulic Pumps

Abstract This article deals with the testing of regulating and non-regulating hydraulic pumps in laboratory conditions. The laboratory test was carried out on the hydraulic device consisting of two separate hydraulic circuits (for testing the non-regulating hydraulic pump and regulating hydraulic pump). A throttle valve or proportional throttle valve is used for loading. During the laboratory tests, the flow efficiency of the non-regulating hydraulic pump at rotation speed n = 1,500 rpm (nominal speed) was η pp = 98.91% (0 MPa) and η pp = 94.97% (20 MPa), and for the regulating hydraulic pump, the values were η pp = 97.57% (0 MPa) and η pp = 94.54% (20 MPa). The determined values of flow efficiency of hydraulic pumps determine the correct operation of the experimental hydraulic laboratory equipment.

Development of Ultra-High-Pressure, High- and Low-Temperature Seals for Cage Throttle Valves

Development of Ultra-High-Pressure, High- and Low-Temperature Seals for Cage Throttle Valves

Experimental analysis of the air-to-water ejector-based R290 heat pump system for domestic application

The aim of this study was to analyze and compare the performance of an 8 kW ejector-based R290 heat pump system for hot water heating applications that operates with two different expansion devices: a throttling valve and a two-phase ejector. The vapor compression system was designed to compare the unit operating in direct expansion and ejector-based working modes under similar operating conditions. The test results were assessed for overall system performance measured by COP and heating capacity and for single-component operation. The ejector mode allowed operation at the same range of ambient temperatures as direct expansion mode with the potential to completely replace the expansion valve. The COP of ejector system was up to 2.6, which was 38% higher than direct expansion when working under similar conditions for an ambient temperature of −12.8°C. Moreover, the COP in direct expansion mode decreased significantly along the decrease of ambient temperature, whereas for the ejector mode this decrease was considerably smaller.

Performance analysis of a two-stage vapor compression heat pump based on intercooling effect

The two-stage compression technology based on intercooling effect effectively improves the low-temperature adaptability of vapor compression heat pump systems. When a two-stage compression system is applied to address a spectrum of low-temperature operating conditions, obvious variations in the capacity ratio and interrelationship between the two compressors will take place, which may result in an instability of system control and compressor burnout during actual equipment operation. Therefore, to refine the control strategy and enhance the practicality of the two-stage compression system, this study mainly focuses on the investigation of the subcooling (SC) parameter and the desuperheating (SH) parameter during the injection process. Both simulation models and experimental testing platform of a two-stage compression heat pump system with a subcooler structure are conducted to explore the effects of intercooling effect under variable operating conditions on various system performance parameters. The results show that as the injection ratio Rinj increases, the changes of SC and SH, ΔTSC and ΔTSH show a parallelogram-like variation, and the turning point of the variation trend is around Rinj = 0.14, stabilized at about 21.55 °C; ΔTSH first increased slowly from 0 °C to 6.04 °C and then rapidly increased to 33.55 °C; the system heat production Qhot and COP were closely related to the change of SC, but not sensitive to the change of SH. Besides, the optimal intermediate pressure calculation equations are determined for different evaporation temperatures, condensing temperatures and cylinder capacity ratios. This study may offer valuable guidance for improving the throttling valve and compressor capacity control strategies in two-stage compression systems.

Structural Optimization Design of Throttle Valve Core for Intelligent Layered Polymer Injection String Controlled By Cable

Optimization Design of Throttling Valve Core Structure for Wired Intelligent Layered Polymer Injection String : Wired intelligent layered polymer in-jection technology can improve the coverage of polymer flooding, alleviate inter-layer conflicts in reservoir development, and improve crude oil recovery. It is an important component of tertiary oil recovery. However, the layered polymer in-jection technology currently used in most domestic oilfields is still the method of fishing and changing the injection nozzle for testing and adjustment. The alloca-tion efficiency of injection volume testing for each layer is slow, with large er-rors, and it is impossible to monitor polymer injection parameters throughout the process. To this end, research has been carried out on the cable controlled intelli-gent layered polymer injection string. By optimizing a highly efficient and low viscosity loss streamlined layered polymer injection throttling device with contin-uously adjustable gaps, the adjustment stroke is shorter and the measurement and adjustment efficiency is higher. Using finite element simulation, the low shear throttle control unit was studied and optimized. By moving the polymer core up and down slightly in the axial direction, the relative gap between the polymer core and the working cylinder was changed to achieve flow adjustment. At the same time, it is necessary to complete the direct reading measurement and adjustment process to form a single pipe layered polymer injection measurement and adjust-ment integration technology. The cable controlled intelligent layered polymer in-jection matching technology connects with the ground intelligent control system through cables to achieve realtime monitoring and online control of polymer flow, pressure, temperature, and other parameters, improving monitoring accura-cy and efficiency, and providing technical support for the construction of the “Digital Intelligence Oilfield”.

Acoustic resonances in an automotive HVAC outlet

In order to better understand the noise generation mechanism of air outlets in an HVAC (Heating Ventilation Air Conditioning) system of a car, investigations were performed in a generic geometry representing a typical air outlet of an automotive car. A hybrid aeroacoustic simulation based on a Large-Eddy Simulation of the incompressible flow coupled with a solver for the acoustic perturbation equations is backed up by an experiment to study the interaction between a throttle valve (used to control the flow rate) and fins (used to guide the flow). Several sound generation mechanisms are identified, of which the so-called Parker-β mode is the most prominent in the sensible frequency range. Both the experimental and simulation results indicate a whistling noise at certain gap lengths between the throttle valve and fins at the frequency of the Parker-β mode. Two different levels of resonance are identified of which one leads to feedback from the acoustic mode to the flow field and one works without feedback. We demonstrate that the latter is established by an efficient excitation of the Parker-β mode by the vortex shedding from the throttle valve if the vortex shedding frequency is close enough to the acoustic frequency.

Method for Predicting Service Life of Cage Throttle Valves

Method for Predicting Service Life of Cage Throttle Valves

Adaptive Second-Order Fixed-Time Sliding Mode Controller with a Disturbance Observer for Electronic Throttle Valves.

In order to enhance the precision and speed of control for electronic throttle valves (ETVs) in the face of disturbance and parameter uncertainties, an adaptive second-order fixed-time sliding mode (ASOFxTSM) controller is developed, along with disturbance observer compensation techniques. Initially, a control-oriented model specifically considering lumped disturbances within the ETV is established. Secondly, to address the contradiction between fast response and heavy chattering of conventional fixed-time sliding mode, a hierarchical sliding surface approach is introduced. This approach proficiently alleviates chattering effects while preserving the fixed convergence properties of the controller. Furthermore, to enhance the anti-disturbance performance of the ETV control system, an innovative fixed-time sliding mode observer is incorporated to estimate lumped disturbances and apply them as a feed-forward compensation term to the ASOFxTSM controller output. Building upon this, a parameter adaptive mechanism is introduced to optimize control gains. Subsequently, a rigorous stability proof is conducted, accompanied by the derivation of the expression for system convergence time. Finally, a comparison is drawn between the proposed controller and fixed-time sliding mode and super-twisting controllers through simulations and experiments. The results demonstrate the superiority of the proposed method in terms of chattering suppression, rapid dynamic response, and disturbance rejection capability.

Experimental study on vibration and noise of throttle valve in water-conveying systems

In the water conveying system, the throttle valve has a great impact on the vibration and noise, which needs to be controlled. In this paper, a noise test bench for throttle valve in water conveying system is established. The vibration, air noise and flow noise are measured under different pressure differences and flow rates for throttle valves with different structures and diameters. The results show that the throttle valve vibration and air noise increase with the increase of pressure difference and flow when the noise is above 70 dB(A). When the pressure difference is more than 0.5MPa, the flow noise of ordinary ball valve is mainly in the high frequency range. The vibration, noise and pipeline flow noise of the low-noise valve with multistage throttling are significantly reduced, and the flow noise is mainly in the low frequency band below 315Hz. The pipe flow noise in front of the throttle valve is broadband which decreases with the increase of frequency. Increasing the pressure behind the throttle valve can reduce the valve vibration under the same pressure difference.

Advanced exergy analysis of a novel air source heat pump system coupled with the liquid receiver and gas-liquid separator

In previous studies, an air source heat pump system coupled with the liquid receiver and the gas-liquid separator was proposed, which improved the defrosting efficiency according to the improvement of the refrigerant mass flow during defrosting and shortened the defrosting time. In this paper, the exergy efficiencies and exergy loss (including endogenous and exogenous exergy loss) of the new system are studied. They are compared with the original air source heat pump system by constructing the advanced exergy study model of the system. Results show that the exergy efficiencies of the compressor, evaporator, and throttle valve of the new system are increased by 0.2%, 2.3%, and 5.9%, respectively. The endogenous exergy loss of the new system accounts for 65.16% of the total exergy loss of the system, and most of the exergy loss in the new system is caused by the components themselves.

Cavitation Characteristics and Structure Optimization of Two-Dimensional Valve Based on Entropy Production Theory

In addition to noise and vibration, cavitation also lowers the efficiency, performance, and working lives of two-dimensional valves. To study the effect of cavitation on the flow characteristics of two-dimensional valves, standard turbulence model and an energy equation model were selected, and the local entropy production rate was defined using the custom field function. The entropy production theory was introduced to numerically simulate the cavitation flow in a two-dimensional valve, and based on this, the structure of the pilot stage of the valve was optimized. The results showed that there was a distinct correlation between the entropy production and the flow characteristics of the valve. When the mass flow rate changed, the entropy production also changed. The turbulent dissipation entropy production always accounted for more than 50% of the total entropy production in the flow field. In the valve sleeve chute area downstream of the valve throttling port, turbulence dissipation entropy production was concentrated; and the energy loss was large. According to the optimization of the structure of this area, the total entropy production of the side-V-slot valve sleeve structure was 7.46% lower than that of the unslotted valve sleeve structure for different valve openings, while the total entropy production of the rear-V-slot valve sleeve structure was 14.31% higher. The energy loss caused by cavitation could be better reduced using a V-shaped groove on the side of the valve sleeve.

RST Switching Bi-controller Based Flatness for an Electronic Throttle Valve

In this paper, an RST switching bi-controller, based on flatness and on Luenberger observers, is designed to control the opening angle change of an Electronic Throttle Valve (ETV), to compensate unexpected external disturbances and to detect sensor faults. Two identified mathematical linear models are established to simulate the ETV for two different positions of the throttle plate. The use of robust RST switching bi-controller based-flatness approach by the development of closedloop control is proposed, in order to obtain a stable system tracking a desired flat trajectory. The switching between the two models using stateflow tool is based on residual values generated by using the Luenberger observers in order to detect and to localize sensor faults occurrence. The observer’s gains are determined using Linear Matrix Inequalities (LMIs) taking into account the stability of the system based on Lyapunov theory. The simulation results show the efficiency of the developed robust switching RST bi-controller based-flatness in terms of tracking the desired angle’s reference trajectory, rejecting disturbances and detecting sensor faults.

Exergy Analysis of Transcritical CO2 Air-Source Heat Pump with Honeycomb Gas Cooler

In order to build an efficient and energy-saving CO2 heat pump system and to improve the heat transfer efficiency of the gas cooler, a novel honeycomb gas cooler with a compact structure, high heat transfer efficiency, and high pressure-bearing capacity was proposed in our previous work. To clarify the components in the system that need further optimization and to improve its performance, an exergy analysis of a transcritical CO2 air-source heat pump system with the novel honeycomb gas cooler is studied in this paper. Based on the second law of thermodynamics, the exergy model of each component in the heat pump system is established, and the irreversible loss of each component is analyzed. In addition, the degree of energy loss of the honeycomb gas cooler is clarified, and the possibility and direction of system optimization are pointed out. The results show that the exergy efficiency of the system is 35.33% under nominal operating conditions, and there is a lot of room for improvement in its energy utilization. The three components with the largest exergy destruction percentage are the compressor, throttle valve, and evaporator in the order of 36.13%, 22.90%, and 19.51%, respectively. These components with high exergy destruction percentages are the main reasons for the large irreversible losses of the system.

Performance improvement of transcritical CO2 refrigeration cycle by integrating vortex tube expansion: Simulation and optimization

Since the critical temperature of CO2 is low and the working pressure is high, cycles using CO2 as a refrigerant are generally transcritical. Considering the large throttling loss and low system performance of the existing transcritical CO2 cycles, this paper proposes a general parameter matching method for transcritical CO2 cycles with vortex tube by using the self-defined functional blocks that can easily and quickly realize the parameter matching of components in refrigeration cycles with diverse architectures. Based on this new method, simulation and optimization of existing transcritical CO2 systems with or without vortex tube are implemented. A two-stage compression transcritical CO2 system with serial vortex tubes is proposed and proven to have a high cooling performance and less exergy loss in comparison with existing transcritical CO2 systems. Furthermore, the number of vortex tube(s) used and the coupling mode of vortex tube(s) with the transcritical CO2 system are also discussed. The results show that for the transcritical system with evaporators greater than two, the performance of the system with parallel vortex tubes is better than that of serial vortex tubes. When there are two evaporators and vortex tubes with a cold mass rate greater than 0.3, the performance of the system with serial vortex tubes is better than that of parallel vortex tubes. Finally, exergy analysis of the improved and existing transcritical CO2 cycles is conducted which shows that the exergy loss caused by the throttle valve is considerably reduced by using the vortex tube.

Throttling Loss Energy-Regeneration System Based on Pressure Difference Pump Control for Electric Forklifts

At present, the hydraulic systems of electric forklifts and traditional internal combustion forklifts are mostly valve-controlled speed-regulation systems, which have large throttling losses and potential energy waste. To further improve the energy-saving ability of electric forklifts, the forklift’s common working conditions are analyzed in this paper. A throttling loss energy-regeneration system based on pressure difference pump control is designed, and the system’s working principle is described. Aiming to deal with the problem that the pump−valve compound speed regulation with constant pressure difference could not realize high controllability and energy saving at the same time, a control strategy for variable pressure difference pump−valve compound speed regulation based on pressure balance control is proposed. The handle signal is positively related to the target speed of the oil cylinder. In the low-speed stage, the closed-loop control of the actual output torque of the motor/generator keeps the pressure difference across the proportional throttle valve unchanged, and the speed adjustment is realized by changing the opening of the proportional throttle valve. In the high-speed stage, the valve opening area is kept unchanged and the target pressure difference is changed to achieve the target speed. Finally, the feasibility of the control strategy is verified through an AMESim simulation, and the minimum pressure difference switching point is determined through experiments. The experiments show that the system’s energy-saving efficiency can reach 21.5% under a 1 t load. With the increase in the load, the system’s energy-saving efficiency can be further improved.

Characterization of two-dimensional cartridge type bidirectional proportional throttle valve

A novel bidirectional proportional throttle valve with a two-dimensional (2D) plug-in structure is proposed in this paper. The valve integrates the 2D valve module and the logic valve into one component, with high integration degree, response speed, and control accuracy. The mathematical model of the 2D valve module is established based on the continuity equation of flow and kinematic equation, and the stability criterion of the valve is established. The effects of the inclination angle, width, and initial overlapping height of the oblique slot and rectangular slot on the dynamic response of the valve are explored by AMESim simulation, and appropriate structural parameters are selected to design and manufacture the prototype valve. A dedicated test bench is built, and the feasibility of the valve design is verified by testing the valve under different system pressures and different load variations. The experimental results show that, at a system pressure of 21 MPa, the prototype valve has a flow rate of 53.5 L min−1, a hysteresis of 0.8%, a linearity of 5%, and a step response time of 6.5 ms. When the analog valve opening is changed by inputting 0.1 Hz signals with different waveforms under different system pressures, the maximum fluctuation of the main spool displacement is less than 1 μm, and the maximum stabilization time does not exceed 110 ms.

Simulation and Structure Optimization of WC–Co Cemented Carbide Cage-Sleeve Type Throttle Valve Core Erosion

Simulation and Structure Optimization of WC–Co Cemented Carbide Cage-Sleeve Type Throttle Valve Core Erosion