Pump Working Research Articles

Research on the seawater-lubricated sliding bearing of a novel buoyancy-regulating seawater pump considering the working depth

ABSTRACT Seawater hydraulic pump is a key component in buoyancy regulation systems. In this paper, a novel full-water-lubricated three-plunger seawater pump was designed in which the plunger suction and drainage are driven by the crankshaft. For this structure, the sliding bearing that supports the crankshaft is a very important factor affecting the pump characteristics. The pressure flow model and the thermal coupling system model of the left/right sliding bearings were established, and the deformation of the left/right sliding bearings in the deep sea environment was analysed by ANSYS Workbench. The change of the fit clearance has a great influence on the work of the hydraulic pump. Different fit clearances at different seawater depths under different radius gaps are obtained. The results show that the fit clearance of the left/right sliding bearings decreases as the depth of the seawater increases. As the depth of the seawater increases, the sliding bearing is gradually changed from the frictional lubrication of the liquid to the boundary friction lubrication. With the increases of the radius gap, the working water depth of the hydraulic pump first increases and then decreases, and the optimal radius clearance and the optimal working depth are obtained.

ТЕРМОДИНАМИЧЕСКИЙ ПРОЦЕСС АГРЕГАТНО-ТЕПЛОВОГО ПРЕОБРАЗОВАНИЯ ТЕПЛОХОЛОДИЛЬНЫХ СИСТЕМ

The performed study shows the result of comparing the technological characteristics of the thermodynamic process of heat exchange of a closed system with the environment of an air heat pump (VTN) with a power of 7 kW obtained experimentally and the work of a recirculation air heat pump (RVTN) with the same power at the same parameters, on the basis of a thermodynamic cycle, at the evaporation temperature of the 100C and three condensation temperatures 300C, 400C, 500C. The result showed that the technological characteristics of the heat pump systems are almost the same.

Physical principles of venous hemodynamics and its mathematical modeling

In physiological conditions, the cardiovascular system (CVS) is a closed circulatory system comprising a pump (the heart), a conduit system (vasculature), and a continuum media (blood) moving through the system. The heart is a major source of energy in this system. It pumps the blood through the two connected loops. From the mechanical point of view, CVS can be represented as a network of flexible tubes filled with a viscous incompressible fluid driven by a periodic energy source. The fluid dynamics are described by Navier-Stokes's equations, representing the fundamental physical principles of mass and momentum conservation. These equations allow computation of the blood velocity field and pressure depending on the forces exerted to the fluid's surface (surface forces) and to a unit portion of the fluid (mass forces). Equations of structural dynamics describe the motion of the vascular wall. The state-of-the-art models incorporate fluid and structure interaction (FSI). The blood flow in various parts of CVS has different features that must be considered during computational simulations. Elastic properties of the veins and arteries are different. The structural features of veins (valves) limit the backward flow. The geometry of venous cross-sections may be circular, elliptic, and dumbbell-shaped. It changes the flow characteristics. Blood rheology plays a significant role in venous flows. According to the mass conservation law, the work of the heart pump provides energy for the arterial flow and determines venous return to the heart atria. Venous hemodynamics comprises a lot of various processes with different physical and biological origins. Complex analysis of a patient requires computational simulations, which provide medical experts with a basis for prognosis and optimal surgical treatment. In this work, we review basic physical principles and modern mathematical models of venous hemodynamics. In conclusion, the blood flow in veins can be considered as a mechanical process. It obeys the fundamental physical principles and can be described by the well-known mathematical models of continuum mechanics. Thus, the flow characteristics can be simulated and predicted in various healthy and pathological conditions basing on the boundary conditions and material properties of the blood and veins.

The Design of A Digital Timing Automatic Feeder With Adjustable Temperature and Humidity

Abstract An automatic feeder for poultry farm with digital display, adjustable temperature and humidity and timing function. It is mainly composed of feeding mechanism, feeding mechanism, travel mechanism, temperature humidity and electrical control box with digital display, can display 24 hours, and with time setting function, in the case of a single intervention to perform automatic feeding work, reduces the labor cost, not only can reduce the time of staff contact with poultry, reduce the spread of disease. With a temperature humidity sensor at the same time, the real-time monitoring and display of breeding field numerical, temperature and humidity can be set to allow upper and lower limits of temperature and humidity fluctuations, and according to the set point control spraying water pump, fan, or heating equipment synchronization work, simplifies the operation of separation equipment, precise control of the feeding environment of temperature and humidity value, achieve the goal of the poultry feeding scientifically.

Heart transplantation in a patient with left ventricular assist device after pump thrombosis: The first case report in Serbia

Introduction. The device thrombosis is one of the most serious complications of the left ventricle assist device implantation with a high mortality and morbidity rate. Case report. A 59-year-old male was implanted by left ventricular assist device Heart Mate II as a bridge to transplantation seventeen months before the onset of a potentially fatal complication ? the thrombosis with the complete obstruction of the device. Despite the aggressive pharmacological treatment following the initial suspicion of the pump thrombosis, the patient condition got worse with the final ?pump off? alarm that marked the discontinuance of the pump work as a result of the complete obstruction by the thrombus. An appropriate occurrence of an adequate donor resulted in a successful surgical treatment ? the heart transplantation. Conclusion. The urgent heart transplantation by the first priority rank, or the device replacement, although technically extremely demanding procedures, are successful treatment options for these patients.

Self-Noise Spectrum Analysis and Joint Noise Filtering for the Sea-Wing Underwater Glider Based on Experimental Data

Using underwater gliders to measure underwater acoustic signals is a new measurement method emerging with the development of platform technology. Although underwater gliders are relatively quiet due to the absence of propellers, vehicle noise generated during motion is still inevitable, which will affect the recorded acoustic data. In this paper, we analyze the self-noise characteristics of underwater gliders based on simulated data by CFD technology for the hydrodynamic flow noise and experimental data acquired in an anechoic-water-tank experiment for the mechanical noise. The mechanical noise covers noises generated by buoyancy regulating (increasing and reducing), pitch regulating, rudder regulating and CTD pump working. According to the analysis results, the flow noise and CTD pump working noise could be ignored for the experimental data processing of sea trials. An experiment was conducted with an acoustic Sea-Wing underwater glider in the South China Sea from July 31 to September 4, 2018. Two kinds of noisy data were recorded, including target signals and ambient noise. All the target signals could be recognized after convolution filtering, except during the buoyancy regulating periods due to the high noise spectrum level. For the recorded ambient noise, in addition to the buoyancy regulating noise, the rudder and pitch regulating noises affected the recorded data. Then based on the acquired knowledge, a joint convolution filtering and thresholding method is proposed to remove the rudder and pitch noises from recorded noisy data. Kernels extracted from data acquired in the anechoic-water-tank experiment are used in the convolution filtering to localize each regulating action and energy thresholding is adopted to determine the duration of each regulation. All the rudder and pitch noises are removed from the recorded noisy data.

The Study of 2 Stage Turbocharging System to Obtain a Positive Pumping Work in Ultra-highly Boosted Range

The Study of 2 Stage Turbocharging System to Obtain a Positive Pumping Work in Ultra-highly Boosted Range

Economic NMPC for Multiple Buildings Connected to a Heat Pump and Thermal and Electrical Storages

This paper studies the impact of different types of energy storage integrated with a heat pump to improve energy efficiency in multiple radiant-floor buildings. In particular, the buildings and the heating generation system are decoupled through a 3-element mixing valve, which enforces a fixed flow rate but a variable temperature in the inlet water entering the building pipelines. The paper presents an optimal control formulation based on an Economic Nonlinear MPC scheme, in order to find the best compromise among different goals: make the heat pump work when it is more efficient, store electrical energy when it is cheap, store thermal energy in the tank when the heat pump is more effective, modulate the inlet water temperature to satisfy the user’s comfort constraints, exploit the buildings thermal inertia. The nonlinearity of the system stems from the variable flow rate into the hot water tank due to the variable action of the mixing valve. The model is also time-varying due to the fact that the heat pump efficiency depends on external conditions. The simulation results show that the proposed optimal control algorithm is able to economically distribute energy among all storages in order to insure cost benefits (almost 20% electricity cost saving) and comfort satisfaction with the feasible computational effort.

Idling Performance under Valve Deactivation Strategy in Port Fuel Injection Engine

This paper investigates the effect of valve deactivation (VDA) on idling performance in port fuel injection (PFI) engine. The test was conducted on 1.6L, 4-cylinder engine with PFI configuration. One of the two intake valves in each cylinder was deactivated (zero lift on deactivated port) and fuel injector was modified to only provide fuel spray on the active intake port. In-cylinder pressure was recorded by the combustion analyzer in order to measure and analyze the combustion characteristics. From the test, there are up to 6% of fuel consumption improvements across all the test conditions. Better combustion stability is achieved at very low idling speed (throttle position, TP = 2%) as a lower coefficient of variation of engine speed (COVrpm) and coefficient of variation indicated mean effective pressure (COVimep) were recorded. Increased intake velocity and swirl flow in the VDA strategy creates more turbulence intensity causing higher heat release rate and faster combustion. However, there is no significant difference in the pumping work during the intake cycle but there is extra pumping work recorded towards the end of expansion stroke due to the very early end of combustion. Therefore, valve deactivation strategy provides limited positive improvement to the idling performance in PFI engine.

Effects of nanoparticle shape and size on the thermohydraulic performance of plate evaporator using hybrid nanofluids

Brines (ethylene glycol, calcium chloride, propylene glycol and potassium acetate)-based hybrid (combinations of alumina, copper oxide, silica and titania with copper nanoparticles) nanofluids have been used as a secondary refrigerant to improve the heat transfer characteristics of the plate evaporator for milk chilling. Effect of nanoparticle combination, shape and size on heat transfer area, pump work, the ratio of heat transfer coefficient to pressure drop, coefficient of performance, performance index, thermal performance factor and exergetic efficiency has been examined theoretically. Copper oxide–copper hybrid nanofluid gives superior performance, while silica–copper hybrid nanofluid performs well in terms of exergetic efficiency. The maximum decrease in effective heat transfer area (5.9%) is found for propylene glycol brine-based copper oxide hybrid nanofluid. Percentage change in heat transfer area and performance index reduces with an increase in the particle size and is maximum for alumina–copper hybrid nanofluid. However, thermal performance factor increases with particle size. Brick-shaped particles show maximum changes in heat transfer area and performance index, while platelet-shaped particles show worse performance. The study reveals that the nanoparticle shape has a strong influence on the plate heat exchanger performance due to a significant deviation in surface area-to-volume ratio.

Kontrol Kualitas Kadar Air Laut Menggunakan Fuzzy LogicUntuk Habitat Ikan Kerapu

The quality of the seawater content for the grouper fish habitat is very influential in the grouper fish development process. Seawater quality for grouper fish habitat depend on temperatur, salinity, acidity (pH), and turbidity of seawater. The quality of seawater can be control by circulation in and out of seawater in the fish pond. This cycle is required to maintain the desired quality of seawater at temperatur 24ºC- 31ºC, salinity 30-33 ppt, dissolved oxygen> 3,5 ppt, and pH 7,5-8,3. In previous studies seawater control systems have been carried out in the form of controls temperatur and pH quality. Other components quality of sea water such as salinity and turbidity due to fish food also influence seawater quality for grouper fish habitat. Component control of sea water in this paper include microcontroller, pump sea water, fresh water pump, sensor and etc. In this paper we are focus on the controlling sea water quality to maintain the quality of grouper fish pools consisting of temperatur, salinity, acidity (pH), and turbidity of seawater. Input this data and the pH of the water read by the sensor will be processed with fuzzy logic to adjust the working of the salt water pump and the freshwater pump until it reaches the setpoint value. Turbidity and temperatur control using the ON-OFF system. The results show that of testing the sea water quality of control system using fuzzy logic in accordance with the calculation of mathematical defuzzyfication with an error of 0%. The values of salinity control system 31,14-32,98 PPT, pH 7,78-8,.2, temperatur 27ºC-29,98ºC, and turbidity level 9,90-14,85 NTU.

THERMAL EVALUATION OF CAVITY RECEIVER USING WATER/PG AS THE SOLAR WORKING FLUID

In this study, a parabolic dish concentrator with a cavity receiver was investigated. Water/ Propylene Glycol (PG) was used as the solar heat transfer fluid. Thermal numerical modelling was developed for prediction of the cavity receiver performance. The water/PG in different volume fractions (VF) of the PG was examined consist of 0%, 25%, 50%, and 55%. The working fluid inlet temperature is investigated in ranging 0oC to 100oC. The results revealed that the thermal efficiency and the cavity heat gain decreased by increasing the GP volume fraction. The pressure drop and pumping work demand decreased by increasing the working fluid inlet temperature as well as decreasing the PG volume fraction in the pure water. Consequently, the pure water had the lowest amount of the pressure drop among the investigated working fluids. The cavity surface temperature increased by increasing the working fluid inlet temperature as well as increasing the PG volume fraction in the pure water. Consequently, the application of the higher amount of PG is recommended for the Bryton cycle.

Analysis of Contact Angle for Metallic Materials in Wastewater Pumps

Immersed wastewater pumps work in aggressive corrosive environments and physicochemical phenomena of corrosion and erosion take place at the liquid-solid interface. Due to the type of interaction between the two media when the basic metallic material is hydrophobic, corrosion phenomena can occur with the erosion due to the movement of the solid particles in the liquid. If the liquid is exposed to the hydrophilic base material, the corrosion phenomena occur in a laminar layer, having partial protection role. In this paper, the contact angle between the metals forming the pump components and the different corrosive media with different composition and pH was measured.

Influence of microclimate boundary conditions in net zero energy settlements on HVAC efficiency

Net zero energy buildings (NZEB) represent reality of new constructions in Europe for environmentally sustainable energy efficiency. The shift to net zero energy settlements represents a further opportunity to achieve extra-energy saving, thanks to utilities sharing, renewables optimization, and microclimate mitigation. This last aspect concerns the opportunity to improve settlements outdoor microclimate conditions in both hot and cold seasons, in a variety of climate conditions, with the purpose to improve occupants’ wellbeing. At the same time, microclimate mitigation at inter-building scale may also involve relatively less severe boundary conditions able to reduce both cooling and heating demand of buildings and better working conditions for HVAC systems, e.g. heat pumps and air-to-air heat exchangers. This extra-energy saving, achievable with no extra costs, may represent an interesting opportunity to be taken into account in net zero energy settlements design and construction. This study analyzes this energy saving in a net zero energy settlement in Italy, built thanks to an on-going Horizon 2020 project. The influence of microclimate mitigation strategies is assessed in terms of energy saving benefits for the heat pump working conditions. Results demonstrate that this further benefit represents a non-negligible, environmentally sustainable, strategy for energy efficiency of NZEB in new inter-building scale developments.

Series and parallel relationship pump performance in FT. Unitas’s practicum tools

Basically, the variation of the pump arrangement in the piping installation is done to get the performance / flow characteristics needed in a particular usage according to the needs, namely the need for a head height that is higher than the flow rate (capacity) or vice versa. Flow regulation method with variations of valve openings (Senen 2004), which is applied in this study with consideration of energy use efficiency, it can be stated that the pump efficiency range of the parallel circuit is high to get a larger flow rate than the series circuit pump. To get the head maximum, the pump efficiency series is smaller than the pump efficiency of the parallel circuit, so that it does not provide an illustration that the optimum pump work has been achieved, so that further research needs to be carried out research with variations in pump rotation (Mastur and Warso 2015) below or above the standard round. But based on the purpose of this study in terms of pump performance, to meet the needs of a high head, the pump installation is arranged in series and vice versa if what is needed in the pump installation system is a high flow rate, the pump is arranged in parallel, so the results of this study have been can meet the needs of practicum for students of Mechanical Engineering Study Program FT. Unitas in terms of how to get the performance of a centrifugal pump installation.

Experimental investigation of an absorption heat pump with organic working pairs

As part of a systematic approach towards the search for alternative absorption heat pump (AHP) working pairs that could potentially provide comparable performance to conventional ones, a previous work performed a detailed theoretical cycle analysis and simulation that revealed concrete correlations between key working fluid thermophysical properties and AHP performance indicators. Following this work, targeted combinations of two organic refrigerants, 2,2,2-trifluoroethanol (TFE) and 2,2,3,3,3-pentafluoropropanol (5FP) and two organic absorbents, 1,3-dimethyl-2-imidazolidinone (DMI) and 2-pyrrolidone (PYR) were tested in a prototype 5 kW AHP, based on a highly compact plate heat exchanger design, which has been previously introduced. The purpose of this effort was to test the findings of the previous work with experimental measurements. The working pair combinations were also subjected to vapor liquid equilibrium (VLE) and viscosity measurements, in order to determine reliable activity coefficient and improve the accuracy of the simulations. The experimental performance data agree well with the COP simulations and show to be consistent with the conclusions derived from the previous theoretical work.

Hydrothermal performance of different alumina hybrid nanofluid types in plate heat exchanger

To enhance the energetic and exergetic performances of the counter-flow plate heat exchanger with corrugations, several experiments were conducted using different Al2O3 hybrid nanofluids as a coolant. The combinations studied were Al2O3–SiC, Al2O3–AlN, Al2O3–MgO, Al2O3–CuO and Al2O3–MWCNT in 4:1 nanoparticle volume ratio and 100% Al2O3 with 0.1 vol% concentration suspended in DI water. Parameters which were varied are the coolant flow rate ranging from 2.0 to 4.0 lpm and coolant inlet temperature from 10 to 25 °C. Effect of coolant flow rates and inlet temperatures on different parameters like heat transfer coefficient ratio, heat transfer coefficient to pressure drop ratio, pump work, performance index and irreversibility has been investigated. A maximum enhancement of around 31.2% has been observed in the heat transfer coefficient for Al2O3–MWCNT (4:1) hybrid nanofluid with the negligible enhancement of 0.08% in the pump work and 12.46% enhancement in the performance index. The maximum enhancement in the irreversibility is around 1.6% for Al2O3–CuO (4:1) hybrid nanofluid. Among the studied nanoparticle combinations, Al2O3–MWCNT (4:1) gives better performance. This study suggests that Al2O3–MWCNT hybrid nanofluid can be a good alternative to enhance thermal performance.

Experimentation on effect of particle ratio on hydrothermal performance of plate heat exchanger using hybrid nanofluid

To quantify the fostering in energetic and exergetic performances of counter flow corrugated plate heat exchanger, several experiments were conducted using Al2O3–MWCNT hybrid nanofluids as coolant. The Al2O3–MWCNT hybrid nanofluids with different nanoparticle volume ratios (5:0, 4:1, 3:2, 2:3, 1:4 and 0:5) and 0.01 v% concentration were used as a coolant for sub-ambient temperature application. Operating parameters which were varied are the coolant flow rate ranging from 2.0 to 4.0 lpm and coolant inlet temperature from 10 to 25 °C. Effects on heat transfer coefficient, heat transfer coefficient to pressure drop ratio, pump work, performance index, irreversibility and exergetic efficiency are investigated. Variation of Nusselt number with Reynolds number has also been studied for different nanoparticle volume ratios. Improvement up to 15.2% has been observed in the heat transfer coefficient for MWCNT (0:5) nanofluid with the negligible enhancement of 0.02% in the pump work and 2.96% enhancement in the performance index. Hydrothermal performance of nanofluids increases with increase in MWCNT ratio in particle mixture due to the negligible effect on pressure drop. No optimum ratio has been found within the studied mixture ratios of nanoparticles.

Impact of Cylinder Deactivation and Cylinder Cutout via Flexible Valve Actuation on Fuel Efficient Aftertreatment Thermal Management at Curb Idle

Cylinder deactivation (CDA) and cylinder cutout are different operating strategies for diesel engines. CDA includes the deactivation of both the valve motions and the fuel injection of select cylinders, while cylinder cutout incorporates only fuel injection deactivation in select cylinders. This study compares diesel engine aftertreatment thermal management improvements possible via CDA and cylinder cutout at curb idle operation (800 RPM and 1.3 bar BMEP). Experiments and analysis demonstrated that both CDA and cylinder cutout enable improved fuel efficient “stay warm” thermal management compared to a stock thermal calibration on a Clean Idle Certified engine. At curb idle, this stock calibration depends on elevated exhaust manifold pressure to increase the required fueling (for thermal management) and to drive EGR. The study described here demonstrates that CDA does not require an elevated exhaust manifold pressure for thermal management or EGR delivery control, whereas cylinder cutout does. In addition to achieving engine-out NOx levels no higher than the stock thermal calibration, both cylinder cutout and CDA enable up to 55% and 80% reductions in particulate matter (PM), respectively. Cylinder cutout demonstrates 17% fuel savings, while CDA demonstrates 40% fuel savings, over the stock six-cylinder thermal calibration. These fuel efficiency improvements primarily result from reductions in pumping work via reduced air flow through the engine. Cylinder cutout reduces the air flow rate via elevated amounts of recirculated gases which are also required to regulate engine-out NOx, resulting in a larger delta pressure across the engine and consequently more pumping work than CDA. CDA reduces the air flow rate by deactivating cylinders, which reduces the charge flow rate and enables a small delta pressure between the intake and exhaust manifolds, resulting in less pumping work by the cylinders. As a result, CDA is more efficient than cylinder cutout. Furthermore, the thermal merits of cylinder cutout require high exhaust manifold pressures, and are subject to the configuration of the exhaust manifold and the exhaust gas recirculation (EGR) path.

Effect of the use of a thermoelectric generator on the pumping work of a diesel engine

Approximately a third part of the energy intake of a light-duty diesel engine is wasted through the exhaust system. Rising awareness of environmental issues together with fuel economy has encouraged research upon energy recovery in internal combustion engines. This article focuses on the application of thermoelectric generators in light-duty diesel vehicles. Most studies available in the literature tend to focus on maximizing the recovered electrical power, not always considering the increase in engine pumping work or testing conditions similar to those of a vehicle. The goal of this article is to evaluate the consequences of the modification of the cross-sectional area in the exhaust pipe that adding a thermoelectric generator implies and to compare them with the electrical power produced by the thermoelectric generator. The effect on the indicated and pumping parameters of the engine under common urban driving conditions is presented. From the results, it can be drawn that within the limits of engine speed and torque tested, the modification of the cross-sectional area does not have a significant negative effect on the engine pumping efficiency. This means that there is potential for the employment of this technique in energy recovery from light-duty vehicles.