Valve Seat Research Articles

Study on the design of control valve for U-shaped noise reduction cage and its fluid flow features and noise

In response to technical issues such as the ineffective noise reduction impact of balanced cage and single-seat control valves, the U-shaped noise reduction cage control valve is investigated and developed. In addition, its equal percentage flow properties and noise reduction impact are good, allowing it to effectively minimize the noise created by the change of fluid parameters of medium such as vapor, gas, and gas-liquid two-phase flow. The flow coefficient and flow properties were analyzed. The noise features of the medium air flow at small and large openings of 30% and 85% are simulated and analyzed, respectively. The pressure, velocity, and temperature of the inlet and outlet air, as well as the sound intensity maximum and sound power level maximum, are also analyzed with the opening curves. A small opening of 30% was selected, and the noise characteristics of cavitation generated by the medium water flow were simulated and analyzed. Together with the pressure and temperature change curves of the incoming water, the volume maxima and density minima of water are studied. The maximum sound intensity and sound power level of water are analyzed using the pressure and temperature curves of inlet water, as well as the cavitation coefficient and the degree of opening. The results of the trial for the pressure resistance of the valve body and the trial for the valve seat seal indicate that both the valve body strength and the valve seat seal meet the specifications. Comparing the noise trial results and simulation results reveals that the sound intensity and sound power level assessed by the trial and simulation are comparable, and the noise reduction impact of the control valve is positive.

TECHNICAL SOLUTION OF PROBLEMS ARISING ON THE SUCTION AND DISCHARGE VALVES OF THR DRILING PUMP

The purpose of the article is to extend the operational life of piston pumps by making beneficial modifications to the suction and discharge valves. The most common cause of mud pump failures is the wears on the valves so there is an urgent need to increase the durability of the inlet and outlet valves. This research will allow us to: - lengthen the functional life of the suction and discharge valves. - develop the mud pump's technical requirements. - enhance the drilling pump's economic effectiveness. Thus, it makes sense to do study on piston mud pump valves in order to improve the technical parameters by making some positive adjustments. A moved forward valve situates which essentially diminishes the affect stretch caused by the effect of a piston pump valve body contrary the valve situates. The valve situate comprises a by and large round and hollow body parcel portion parcel with a fixing surface which is slanted from the external surface of the round and hollow body parcel toward an insides throat of said round and hollow body parcel. The valve body comprises a for the most part disc-shaped parcel and a truncated funnel shaped parcel. An elastomer embed is gotten in a groove within the valve body. The cone shaped parcel of the valve comprises an inclined confront, counting a metal parcel and an elastomeric parcel shaped by the elastomeric embed. Within the valve situate of the present innovation, an annular weight alleviation groove within the round and hollow body parcel of the valve situate permits the inclined confront of the valve situate to flex subsequently calming a noteworthy sum of the affect stack between the restricting confront of the valve gathering. Keywords: suction valve, discharge valve, valve wears, valve seat, poppet valve, piston mud pumps.

Composite structure of the magnesium ball valve element for a drilling well

In the oil industry, balls are used in the process of hydraulic fracturing (HF). The material that meets the basic requirements for HF balls is magnesium. Soluble magnesium balls are designed to activate HF couplings. When the coupling seat is reached, during the pumping of HF fluid, the ball temporarily blocks the passage section inside the shank column, which makes it possible to create excess pressure and open the windows of the HF coupling. However, since magnesium has a low density, in drilling fluids with a high density, leaky contact of the ball with the valve seat is possible due to insufficient gravity. This may lead to leakage of the working fluid. The purpose of the work is to create and study a method of manufacturing a ball aimed at weighing it down. The developed method of manufacturing a two-layer ball valve element by stamping is described. The two-layer ball consists of a magnesium shell, inside which a steel ball is placed. A steel ball is placed in a magnesium cylindrical glass with a bottom, the glass is closed with a magnesium lid. The resulting composite assembly is deformed by being compressed with two punches with ends in the form of hemispheres until the ends of the cylindrical cup are tightly closed. As a variant, the shell of the ball is proposed to be made of Mg90 grade magnesium. It is theoretically established that the mass of a bimetallic ball is 2.74 times larger than a magnesium ball. Modeling of stamping of a composite billet is performed in order to establish the possibility of obtaining a ball according to the proposed method. The stress-strain state of a composite billet in the process of shaping is considered. Successful computer simulation of the process gives grounds to recommend the proposed method for implementation in a real experiment. The smallest value of the ratio of the cylinder wall thickness to its height is also established, which ensures the stability of the cylinder wall during deformation.

Dynamic Characteristics Prediction Model for Diesel Engine Valve Train Design Parameters Based on Deep Learning

This paper presents a comprehensive study on the utilization of machine learning and deep learning techniques to predict the dynamic characteristics of design parameters, exemplified by a diesel engine valve train. The research aims to address the challenging and time-consuming analysis required to optimize the performance and durability of valve train components, which are influenced by numerous factors. To this end, dynamic analyses data have been collected for diesel engine specifications and used to construct a regression prediction model using a gradient boosting regressor tree (GBRT), a deep neural network (DNN), a one-dimensional convolution neural network (1D-CNN), and long short-term memory (LSTM). The prediction model was utilized to estimate the force and valve seating velocity values of the valve train system. The dynamic characteristics of the case were evaluated by comparing the actual and predicted values. The results showed that the GBRT model had an R2 value of 0.90 for the valve train force and 0.97 for the valve seating velocity, while the 1D-CNN model had an R2 value of 0.89 for the valve train force and 0.98 for the valve seating velocity. The results of this study have important implications for advancing the design and development of efficient and reliable diesel engines.

Exhaust Valve Leakage Analysis on Main Engine at KM. Tonasa Lines XV

The exhaust valve is one of the components on the main engine that functions to close and open the flow of exhaust gas from the combustion chamber or liner, both in four-stroke and two-stroke diesel engines. The research was carried out for ±10 months on the Tonasa Line XV ship. The purpose of this study was to determine the cause of the exhaust valve leak. Primary data were obtained directly through interviews with related parties. Secondary data is obtained from data collection institutions and published to the data user community, in this study in the form of journals in e-journals. The results obtained from research identification show that first: the occurrence of spindle and seat valve wear due to a lack of maintenance systems, second: excess working hours of exhaust valves, third: clogged cooling water system. The identification of the research found that the cause of the exhaust valve leak was due to worn spindle and seat valves, excess working hours and blockage of the cooling water path. The ways that can be done to avoid damage are by grinding the spindle and seat valve, maintenance according to working hours, and cleaning the cooling water.

Study of the periodic thermal contact between exhaust valve and its seat in an internal combustion engine

The focus of internal combustion engine development for urban vehicles is shifting towards reducing materials by making them lighter. In order to maintain thermal and flow levels, a model was developed to study the thermal behavior of valve seats during periodic contact, which can also help improve engine performance and fuel efficiency. The model, composed of two cylindrical bars in periodic contact, takes into account the evolution and topography of the contact surface. The model's performance was evaluated through various experimental studies and showed a maximum difference of 5.05% with experimental values, in good agreement with previous literature. The results showed that heat flux increases with increasing contact frequency and thermal diffusivity affects conductive transfer. This model can be used by manufacturers to evaluate cylinder head temperature and by the automotive industry to improve heat transfer in engines.

Experimental Research and Numerical Simulation of Laser Welding of 303Cu/440C-Nb Stainless-Steel Thin-Walled Natural-Gas Injector for Vehicles.

This paper presents the results of research on laser lap welding technology of heterogeneous materials and a laser post-heat treatment method to enhance welding performance. The purpose of this study is to reveal the welding principle of austenitic/martensitic dissimilar stainless-steel materials (3030Cu/440C-Nb) and to further obtain welded joints with good mechanical and sealing properties. A natural-gas injector valve is taken as the study case where its valve pipe (303Cu) and valve seat (440C-Nb) are welded. Experiments and numerical simulations were conducted where the welded joints' temperature and stress fields, microstructure, element distribution, and microhardness were studied. The results showed that the residual equivalent stresses and uneven fusion zone tend to concentrate at the joint of two materials within the welded joint. The hardness of the 303Cu side (181.8 HV) is less than the 440C-Nb side (266 HV) in the center of the welded joint. The laser post-heat treatment can reduce the residual equivalent stress in the welded joint and improve the mechanical and sealing properties. The results of the press-off force test and the helium leakage test showed that the press-off force increased from 9640 N to 10,046 N and the helium leakage rate decreased from 3.34 × 10-4 to 3.96 × 10-6.

ABRASIVE WEAR RESISTANCE OF FE3AL AND STELLITE 6 COATINGS FOR THE PROTECTION OF VALVE SEATS SURFACES

The development of a technology that increases the service life of valve seats in CNG/LNG-powered vehicles requires the appropriate selection of material and the technology of its application. Commercially used valve seat materials show accelerated wear under operating conditions, especially in natural gas vehicle engines. The authors developed a new material concept and a new technological concept for the protection of the valve seat in CNG/LNG-powered vehicles. This article aims to present the first stage of tribological research. Two materials were used in the research: Stellite 6 alloy and Fe3Al intermetal. A commonly used material for valve seats of combustion engines is Stellite 6. The Fe3Al is the new proposed material coating for the protection of the valve seats of internal combustion engines. This article compares the abrasive wear resistance of these materials. The abrasion tests were performed on a T-11 pin-on-disc tester, and the counter-sample was steel S235JR. The test conditions were similar to those prevailing during the operation of the valves in the head of the internal combustion engine, without the influence of temperature. The obtained results indicate that the Fe3Al intermetal is characterized by a lower coefficient of friction and lower wear intensity than Stellite 6. The results confirm that the Fe3Al phase is a prospective material to be used as a protective material on the valve seat of vehicles.

Design of Plastic Mould for One-way Valve Seat of Barrel Sailor Pressure Pumping Device

Many plastic products in our lives are produced mainly by special moulds. If there is no good mould, the quality of the product will be significantly reduced. A good set of moulds can reduce labour time and save costs, solve the problem of injection mould in the production of one-way valve seats, make it easy to take off and reduce bubbles, and improve the quality of products. It is of great significance to study and design related moulds. This paper analyzes the process of a one-way valve seat, studies the moulding principle of plastic parts, analyzes the appearance and shape of plastic parts, and optimizes the parting surface design. The reasonable choice of mould frame makes the structure more straightforward to produce and manufacture.

Derivation and validation of heat transfer model for Spark-Ignition engine cylinder head

The valve train is located in the engine cylinder head, which has various operational heat transfer mechanisms to accommodate the combustion process. Most heat transfer studies in this area have only addressed medium-to high-power vehicles at a single running speed. In this study, a model of an air-cooled underbone motorcycle valve, valve seat, and engine cylinder head was tested to determine the thermal characteristics using actual engine operating conditions at low, medium, and high engine speeds. One-dimensional thermal simulation analyses were conducted to obtain the instantaneous heat-transfer coefficients of an actual engine. The average thermal value was determined as the boundary condition in the three-dimensional thermal analysis. A three-dimensional model was prepared using the ANSYS commercial computational fluid dynamics software package. The results show that as the engine speed increases, so does the thermal load toward the component in the engine cylinder head. The strongest temperature regions were concentrated around the combustion face. The exhaust valve held most of the heat, with the valve neck recording the highest temperature. For the intake valve, the combustion face registered the majority of the heat. The heat flux intensity was gathered in the contact surface area between the valve and its seat, between the valve stem and guide, and between the stem guide and tip section. A thermal survey was used to validate the three modelling results for two separate engine datasets. The cumulative relative errors for intake and exhaust valve seats for low engine speeds were 3.73% and 0.17%, respectively. The intake and exhaust valve seats had cumulative relative errors of 4.12% and 0.70%, respectively, at intermediate speeds. This methodology provides valuable information for analysing the heat characterisation of air-cooled engines. It can also be a useful blueprint for the automotive industry and other researchers involved in thermal measurements.

An experimental study on wear, deposits, performance, and emissions of bio-fueled motorcycle engines

ABSTRACT The study investigated the impact of gasoline and ethanol-gasoline blend E5 on motorcycle engine wear, deposits, performance, and emissions following an endurance run test. The dimensions, appearance of the major components, and engine performance and emission have been measured to compare. Compared to the E0 case, the ring grooves and piston’s skirt in the case of E5 fueling were relatively cleaner. The piston skirt wear was 0.06 mm for E0 and 0.04 mm for the E5 case. After the endurance run test, the mass of deposits on the intake valves and valve seats was 247.3 mg for the E0 and 323.8 mg for the E5 case. In addition, the electrode gap of the spark increased gradually up to 50% after 200 h of running for E0, but the gap was only 31.5% raised for E5. A slight increase of 1.63% and 1.51% on average brake power was observed for E0 and E5 cases after 100 h of operation. However, the observed power drop of 2.55% for E0 and 1.86% for E5 as the test engines reached 200 h of operation. The CO emission was reduced by 1.73% to 4.81% for E0-engine and 0.58% to 2.35% for E5-engine after 100 h. But, after 200 h, CO increased 1.12% to 8.07% for E0 and 0.24% to 0.38% for the E5-engine within speeds 4000 rpm to 7000 rpm. HC increased by 4.69% to 14.14% for the E0-engine and 1.55% to 6.98% for the E5-engine after the endurance run test. There was an unpredictable tendency of NOx emission after 100 h and 200 h of operation for both test engines.

Cavitation state recognition for control valve using AlexNet-type neural networks with three-channel images transformed by time series

The control valve is a crucial component with high switching frequency in coal liquefaction systems. Its performance exerts a great influence on the long-term operations in the coal chemical technology. Cavitation is a key factor affecting the control accuracy and surface morphology of the control valve; hence, it will further shorten the service life of the control valve. A cavitation state recognition model based on vibration acceleration time series is proposed in this paper, and the cavitation stage in the valve is identified accurately. Three vibration acceleration sensors are attached to the valve seat to measure cavitation-induced vibration data. The collected time series is divided into fragments based on the non-overlap moving window method, and these fragments are converted into feature maps using the Gramian angular field transform. These feature maps are then input into AlexNet to train the cavitation state recognition model. The experimental results show that recognition accuracy could be improved effectively upon the increase in the length of the time series fragment, and the proposed model has a similar prediction accuracy on unfamiliar datasets. Compared with no noise, the recognition accuracy could reach to 95% when the moving window length is 150 and the signal-to-noise ratio is equal to 5 dB. Furthermore, the proposed model could still achieve good recognition results under mixed open conditions.

Research on the sealing performance of a seawater stop valve considering roundness error used in an 11000-m manned submersible

The sealing performance is a critical characteristic of the stop valve used in an 11000-m manned submersible, while it is a challenge when the pressure difference at the valve port reaches 120 MPa. Previous studies have mainly focused on the effect of surface microtopography, such as the surface roughness, on sealing performance. They believed that rougher surfaces will result in more severe leaks. However, in the sealing experiments of two stop valves with different materials and surface roughness in this paper, the relationship between surface roughness and sealing performance is inconsistent with existing research. There should be another factor that affects the sealing performance of the stop valves more strongly. So a new sealing principle considering the roundness error is proposed. The sealing force, which is determined by the environmental pressure, creates radial deformation on the valve port. The radial deformation of the valve seat is analyzed by a validated finite element analysis (FEA) at various environmental pressures. Then the critical environmental pressure at which the leak stops is obtained when the radial deformation is greater than the roundness error, which is measured. The results show that the critical environmental pressure obtained by FEA is very close to that obtained by experiment. So the consideration of the roundness error of the valve seat is accurate and helpful to the research on the sealing performance of the ultra-high pressure stop valves, and the sealing performance of the ultra-high pressure stop valve can be easily evaluated by FEA.

Chasitermespax, a new genus and species of soldierless termite (Termitidae, Apicotermitinae) from the island of Trinidad.

Chasitermespax Scheffrahn & Carrijo gen. et sp. nov. is described from workers collected from a single colony in the Northern Range of Trinidad. The shape and texture of the unsclerotized enteric valve, tubular shape of the enteric valve seating, and prominent spherical mesenteric tongue of C.pax are the diagnostic characters for both the genus and species. A Bayesian phylogenetic analysis using the COI gene and including all neotropical Apicotermitinae genera described to date supports the new genus as a distinct terminal.

Study on the design of ball valve based on elastic ring valve seat structure and fluid characteristics and fatigue strength

Aimed at the technical problems such as the influence of granular medium on spring pre-tightening force sealing, a new ball valve based on elastic ring valve seat structure is studied. The spring plate type valve seat structure is designed to cooperate with the ball core for sealing, and the blade spring coil is used to cooperate with the ball core for sealing in the spring plate type valve seat structure. Wherein the supporting back ring supports the blade leaf spring on the outer side to enhance and protect the role of the blade spring coil. The design without the spring cavity avoids the problem of sealing failure caused by medium entering into the spring cavity and affecting the compression spring, and avoids the situation that the valve seat can be sealed with the ball core by pre-tightening the compression spring, thus avoiding the problem of sealing failure caused by the valve seat sticking on the valve body. The mechanical and flow characteristics are studied and analyzed by the ball valve characteristic test system. The stem torque, unbalance torque, flow characteristics and flow coefficient variation at different nominal diameters are analyzed. The seal allowable squeeze stress and seal surface pressure are analyzed, and the seal is stable and reliable with the seal pressure meeting the seal design criteria. The fluid dynamics simulation analyzes the velocity, pressure and flow traces of the fluid flowing through the ball valve under three opening degrees: fully closed, half open and fully open, the maximum velocity-pressure and opening degree variation curves of the inlet and outlet, the maximum velocity-pressure and opening degree variation curves of the inlet and outlet under different nominal diameters and the flow resistance coefficient curves. Static strength analysis was done for the ball core and spring plate seat structure to obtain the stress, displacement, strain and safety factor. The fatigue strength of the ball spool and spring-loaded plate seat structure was analyzed, and the total number of lives (cycles) and load factors were obtained, and the results show that the fatigue strength of the ball spool and spring-loaded plate seat structure is safe and the fatigue strength meets the requirements. Ball valve pressure test, low pressure sealing test and high pressure sealing test, valve body strength and ball valve sealing performance all meet the requirements.

Design of Valve Seating Buffer for Electromagnetic Variable Valve System

An electromagnetic variable valve (EMVV) system can significantly reduce pumping loss and discharge loss of the engine by enabling variable valve timing and variable valve lift. However, the valve seat easily produces a larger impact collision with the engine cylinder head because of fast valve seating velocity, greatly decreasing engine life. Therefore, in this paper, a valve seating buffer (VSB) is designed to solve the problem of large electromagnetic valve seating impact. Firstly, a scheme of an EMVV system with embedded buffer is proposed, the collision model is established to resolve the problem of the soft landing of the valve and the effectiveness of the model is verified by experiment. In addition, the structure, material and dimension parameters of the proposed buffer are designed, and some key parameters of the buffer are optimized by the Nelder–Mead (N–M) algorithm. Finally, a co-simulation model of the actuator and the buffer is built, and the valve seating performance is analyzed. The co-simulation results show that the valve seating velocity and rebound height of the EMVV system with the designed buffer are reduced by 94.8% and 97%, respectively, which verifies the advantages of the designed VSB.

Малозольные моторные масла: технологии и тенденции применения

. Analytical information is presented on the development and implementation of low- and ash-free motor oils in the specifications for promising automotive engines, taking into account global trends in the development of engine building. The technologies of ash-free alkaline number boosters of various composition and structure in motor oils, the features of the use of oils of new categories, including restrictions on the content of sulphate ash in them, are considered. The improvement of the design of these engines, the expansion of the range of their operating conditions determines the specifics of the requirements for the physico-chemical properties of the engine oils used, which in turn provides for changes in the chemical composition of the latter. The increased content of these elements and sulfate ash has a negative impact on the efficiency of the systems for cleaning and neutralizing harmful exhaust gas particles, and sulfate ash additionally negatively affects the formation of deposits in the zone of the cylinder piston group, on the blades and in the turbocharger nozzle, as well as on valve seats. The necessary neutralizing oil reserve, expressed by the value of its base number, is provided by the use of, in particular, low-ash magnesium sulfonates, amino derivatives of ash-free boosters of various chemical composition and structure in the oil. During the development of the oil SAE 5w-30, for the first time, the possibilities of using functional additives of domestic production in its composition were taken into account. At the stage of formulation of the additive package, the synergism of the antioxidant action of the ammonium salt of dialkyldithiophosphoric acid with tetra(2-ethylhexyl) thiuram disulfide obtained by oxidation of di(2-ethylhexyl) was established sodiumdithiocarbamate with an aqueous solution of iodine. A mixture of these heteroorganic compounds in an equimass ratio is recommended as a new high-temperature primary antioxidant. Additional studies have established a sufficient level of anti-wear properties, as well as the inhibitory effect of this mixture in the reactions of accumulation and decomposition of hydroperoxides.

Influence of the valve on the performance of two cylindrical valved holding chambers

The use of valved holding chambers (VHCs) is recommended when pressurized metered dose inhalers (pMDI) are prescribed. These medical devices decrease actuation-inhalation coordination difficulties, improve drug delivery and reduce oropharyngeal deposition. In this work, an in vitro and in silico analysis of two commercial VHCs is performed. Both devices are antistatic and are similar in length, volume, shape, but have different valve design (valve seat and flaps). Experimental results, using a Next Generation Impactor, showed that the VHCs differ in their performance, so they are not interchangeable. However, when flaps are not present in commercial VHCs and its 3D prototypes (designed with the same body volume and wall material), the differences in emitted fraction are not significant. In addition, studies performed with computational fluid dynamics showed that the highest particle deposition occurs by impact on the valve. Thus, while multiple factors of VHCs influence the delivered dose, in this work it has been shown that the main one to be considered is the valve design. • An in vitro and in silico analysis of two commercial VHCs is performed. • VHCs are not interchangeable when used with valve flaps. • The differences in emitted fraction are not significant when the flaps are removed. • CFD studies show that the highest particle deposition occurs by impact on the valve. • It has been shown that the main factor to be considered is the valve design.

Valve seat angle influence on losses in valves for steam turbines

Losses in valve assemblies have a significant influence on turbines´ efficiency. Therefore, performing pressure loss analysis to enhance the valve design has always been one of the traditional issues. Valves can differ in many ways in terms of their design. This paper aims to show the influence of the valve seat angle, which is one of the characteristic design dimensions. In order to achieve this, different results from a wide range of measurements on two different models are used. Regarding the first model with a 60° valve seat angle, the measurement was performed in the Aerodynamic laboratory of the Institute of Thermomechanics of the Czech Academy of Sciences. The measurement of the second model with a 90° valve seat angle was performed in the Doosan Skoda Power experimental lab. Differences are described in the form of a total loss coefficient and a flow contraction coefficient. The results are complemented by flow fields from numerical simulations performed on both valve models using a package of ANSYS software tools.

Development of a pneumatic actuated low-pressure direct injection gas injector for hydrogen-fueled internal combustion engines

Mixture formation is one of the greatest challenges for the development of robust and efficient hydrogen-fueled internal combustion engines. In many reviews and research papers, authors pointed out that direct injection (DI) has noteworthy advantages over a port fuel injection (PFI), such as higher power output, higher efficiency, the possibility of mixture stratification to control NOx-formation and reduce heat losses and above all to mitigate combustion abnormalities such as back-firing and pre-ignitions. When considering pressurized gas tanks for on-vehicle hydrogen storage, a low-pressure (LP) injection system is advantageous since the tank capacity can be better exploited accordingly. The low gas density upstream of the injector requires cross-sectional areas far larger than any other injectors for direct injection in today's gasoline or diesel engines. The injector design proposed in this work consists of a flat valve seat to enable the achievement of lifetime requirements in heavy-duty applications. The gas supply pressure is used as the energy source for the actuation of the valve plate by means of a pneumatic actuator. This article describes the design and the performed tests carried out to prove the concept readiness of the new LP-DI-injector.