Fluid Property Effects on Power Consumption in a Hydraulic System at Low Temperatures

2020 ◽  
Author(s):  
Paul Michael ◽  
Cecilia Dai ◽  
Kimberly Rodriguez
Keyword(s):  
Low Temperature ◽  
Power Consumption ◽  
Low Temperatures ◽  
Hydraulic System ◽  
Rotational Frequency ◽  
Input Power ◽  
Operating Conditions ◽  
System Response ◽  
Hydraulic Systems ◽  
System Power

Abstract Hydraulic systems that are operated outdoors during winter can be exposed to extreme low temperatures. Low temperature thickening of the hydraulic fluid can increase power consumption, cause pump cavitation, and stall system actuation. In this study, the response time and power consumption of a hydraulic vehicle restraint system that is used outdoors year-round was evaluated at low temperatures. This safety device incorporated proximity switches that triggered a machine “fault” when the time delay between the locked and unlocked positions exceeded 8 seconds. Straight- and multi-grade ISO VG 32 and 46 fluids were compared in the device. The multi-grade oils were able to function at a lower temperature without faulting. The effect of system operating conditions and fluid properties on pump input power was evaluated. The input power was determined from measurements of pump rotational frequency and torque. Pump torque increased as the oil temperature decreased. As a result, low-temperature operating conditions resulted in a higher system power requirements. An empirical model was developed to investigate the effects of turbulent and laminar flow conditions on the hydraulic system power requirements. A comparison of model standard errors revealed that viscosity-dependent laminar losses had a greater impact on system performance than density-dependent turbulent losses. Since the viscosity coefficients of the fluids were very high at the test temperature, it was theorized that pressure drop in the hydraulic lines was affecting system response. Hydraulic system simulations were conducted via Automation Studio. Cylinder retraction velocities were evaluated with larger ID cap- and rod-side hoses. Increasing the cap-side hose diameter enhanced the low temperature performance of the system. Changes to the rod-side hose had minimal effect. These results provide new insights for system design and the formulation of hydraulic fluids used in extreme low temperature operations.

Experimental Study on Miniature-Refrigeration System

2012 ◽  
Vol 531-532 ◽  
pp. 584-587
Author(s):  
Juan Juan Yang ◽  
Ke Li ◽  
Xin Yang Cui
Keyword(s):  
Power Consumption ◽  
Water Temperature ◽  
Compression Ratio ◽  
Cooling System ◽  
Operating Conditions ◽  
Operation Condition ◽  
Environment Temperature ◽  
Chilled Water ◽  
Compressor Power ◽  
System Power

A prototype of miniature cooling system was developed, which mainly consists of the miniature compressor from DONG YUAN and a spiral-tube evaporator designed by ourselves. The performances of the prototype with different parameters were tested. The influence of ambient temperature, chilled water temperature on the performance of the cooling system were analyzed. The best operating conditions and the optimum amount of refrigerant were obtained. Conclusions were gotten as follows:1) With environment temperature rising, compression ratio increases, system power consumption increases and refrigerating capacity COP decreases. 2) With chilled water temperature rising, compression ratio and power consumption decrease, refrigerating capacity increases, and COP increases rapidly.3) Paper gets system performance: refrigerating capacity is 63 W, compressor power consumption is 24.5 W, COP value is 2.57. in operation condition: refrigerant amount is 40g, environment temperature is 30°C, chilled water temperature is 40 °C, chilled water mass flow is 45 kg/h.

scholarly journals Hybrid Control Accommodation forWater-asset Management of Hydraulic Systems Subjected to Large Operating Conditions

2007 ◽  
Vol 2 (3) ◽  
pp. 241
Author(s):  
Eric Duviella ◽  
Pascale Chiron ◽  
Philippe Charbonnaud
Keyword(s):  
Asset Management ◽  
Hydraulic System ◽  
Hybrid Control ◽  
Operating Conditions ◽  
Hydraulic Systems ◽  
Selection Technique ◽  
Operating Modes ◽  
Transfer Delay ◽  
Simulation Results

The Hybrid Control Accommodation (HCA) strategy was proposed to improve the water-asset management of hydraulic systems by resource allocation and setpoint assignment. Hydraulic system dynamics are taken into account during the setpoint assignment step which consists in controlling gates for large operating conditions. For hydraulic systems subjected to strong disturbances, transfer delays are variable, thus different operating modes must be considered. A multimodelling method, associated to a selection technique of transfer delay, allowing for the determination of the number of models, is proposed. The simulation results on the first reach of the Neste canal show the effectiveness of the HCA strategy.

scholarly journals LOW TEMPERATURES EFFECT ON THERMAL CONDITIONS OF DZ-98 AUTOGRADER HYDRAULIC UNITS

2020 ◽  
Vol 17 (3) ◽  
pp. 316-327
Author(s):  
T. N. Okhlopkov
Keyword(s):  
Heat Transfer ◽  
Surface Temperature ◽  
Ambient Temperature ◽  
Thermal Regime ◽  
Low Temperatures ◽  
Hydraulic System ◽  
Operating Conditions ◽  
Working Fluid ◽  
Climatic Data ◽  
Joint Stock Company

Introduction. The article discusses the climatic conditions of Yakutia, as well as the cooling process of the hydraulic system of DZ-98 motor grader in order to prevent violation of the thermal regime of hydraulic units under the influence of low temperatures, taking into account the wind blowing and operating conditions. The surface temperature of the hydraulic units was measured on January 16, 2018 in the city of Yakutsk on the basis of Yakutdorstroi joint-stock company at an ambient temperature of -42 ° С.Materials and methods. To ensure a reliable operation of the hydraulic system at low temperatures, hydraulic units must provide a supply of working fluid under pressure, regardless of changes in ambient temperature. The thermal regime of hydraulic units is characterized by three main parameters: pressure, temperature and volume. In the North, where the ambient winter temperature varies from -27 ° С to -49 ° С, the absolute temperature is the determining parameter. Studying the problem, theories of heat conduction and heat transfer in solids, hydrodynamics, and differential equations were used.Results. Natural and climatic data, as well as the recorded surface temperature of hydraulic units, allow to determine the number of days with a critically negative temperature, the heat transfer of hydraulic units and the regularity of its change depending on the operating mode.

The Effect of Different Designs on Performance of a Fluid Power Control System

2014 ◽  
Author(s):  
Tahany W. Sadak ◽  
Ahmed Fouly
Keyword(s):  
Hydraulic System ◽  
Dynamic Performance ◽  
Time Lag ◽  
Control Valve ◽  
Operating Conditions ◽  
Flow Control Valve ◽  
Hydraulic Systems ◽  
Supply Pressure ◽  
High Speeds ◽  
Hydraulic Servo

Hydraulic systems are characterized by their ability to import large forces at high speeds and are used in many industrial motion systems, also, in applications where good dynamic performance is important. This research concentrates on static and dynamic performance of a linear hydraulic system under different operating conditions in case of connecting an Electro Hydraulic Servo Valve (EHSV) and a Proportional Directional Flow Control Valve (PDFCV). High technology is used for measuring and recording the experimental results which achieves accurate evaluations. Experiments have been conducted in case of no-load and under load 5560 N. Supply pressure has been changed from 10 up to 50 bar. Effect of pressure and load variation on hydraulic system performance has been studied. It is concluded that increasing the load decreases the bandwidth frequency, but increasing the supply pressure increases the bandwidth frequency. Comparing the time lag of the system considering connecting the (EHSV) with that in case of connecting (PDFCV), it’s observed that in the present investigation the time lag improves by about 86.4% in case of free-load and by about 95.3% in case of system loaded.

scholarly journals Washable, Low-Temperature Cured Joints for Textile-Based Electronics

Electronics ◽  
2021 ◽  
Vol 10 (22) ◽  
pp. 2749
Author(s):  
Jerzy Szalapak ◽  
Vitalij Scenev ◽  
Daniel Janczak ◽  
Lukas Werft ◽  
Sigrid Rotzler ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Low Temperature ◽  
Power Consumption ◽  
Low Temperatures ◽  
Wearable Electronics ◽  
Simple Method ◽  
Stencil Printing ◽  
Lower Power ◽  
Pick And Place ◽  
Silver Flakes

Low-temperature die-attaching pastes for wearable electronics are the key components to realize any type of device where components are additively manufactured by pick and place techniques. In this paper, the authors describe a simple method to realize stretchable, bendable, die-attaching pastes based on silver flakes to directly mount resistors and LEDs onto textiles. This paste can be directly applied onto contact pads placed on textiles by means of screen and stencil printing and post-processed at low temperatures to achieve the desired electrical and mechanical properties below 60 °C without sintering. Low curing temperatures lead to lower power consumption, which makes this paste ecological friendly.

Compact Fluid-Borne Noise Silencers for Aviation Hydraulic Systems

2015 ◽  
Author(s):  
Arne Waitschat ◽  
Frank Thielecke ◽  
Peter Kloft ◽  
Christian Nisters ◽  
Robert M. Behr ◽  
...  
Keyword(s):  
Hydraulic System ◽  
Operating Conditions ◽  
Hydraulic Systems ◽  
Expansion Chamber ◽  
Helmholtz Resonators ◽  
Incremental Development ◽  
Fundamental Frequencies ◽  
Safety And Reliability ◽  
Radial Dimension ◽  
Commercial Aircrafts

The aviation environment holds challenging application constraints for efficient hydraulic system noise reduction devices. Besides obligatory strong limits on component weight and size, the high safety and reliability standards demand simple and maintenance-free silencer solutions. Hence, basic Helmholtz-Resonators and inline expansion chambers are state-of-the-art aboard commercial aircrafts in service. Unfortunately, they do not meet today’s noise attenuation performance aims regarding passenger comfort and equipment durability. Furthermore, production and installation costs have to be considered, plus particular aircraft operating conditions. Commercial aircrafts come with relatively high operating pressures of 210/350bar (3000/5000psi) and fluid-borne noise fundamental frequencies up to approximately 1200 Hz for some of the hydraulic pumps. This conference contribution discusses a new compact approach for an inline expansion chamber, named DiscSilencer that accounts for the mentioned aviation constraints. The silencer chamber is designed as smooth expansion in only one radial direction relative to the connected piping. The perpendicular radial dimension is kept identical to the piping diameter. This results in a flat rectangular cross area of the flow passageway instead of a circular shape, enabling new options for installation and further incremental development. In this paper, the modelling and experimental validation of such an unconventional hydraulic silencer are presented.

In situ Tensile Experiments at Low Temperatures on Niobium Single Crystals by H.V.E.M.

1975 ◽  
Vol 33 ◽  
pp. 58-59
Author(s):  
F. H. Louchet ◽  
L. P. Kubin
Keyword(s):  
Electron Microscope ◽  
Transition Temperature ◽  
Low Temperature ◽  
Slip System ◽  
Low Temperatures ◽  
Tensile Axis ◽  
Image Intensifier ◽  
Screw Dislocations ◽  
Source Operation

Experiments have been carried out on the 3 MeV electron microscope in Toulouse. The low temperature straining holder has been previously described Images given by an image intensifier are recorded on magnetic tape.The microtensile niobium samples are cut in a plane with the two operative slip directions [111] and lying in the foil plane. The tensile axis is near [011].Our results concern:- The transition temperature of niobium near 220 K: at this temperature and below an increasing difference appears between the mobilities of the screw and edge portions of dislocations loops. Source operation and interactions between screw dislocations of different slip system have been recorded.

INVAR M93

Alloy Digest ◽  
2008 ◽  
Vol 57 (1) ◽  
Keyword(s):  
Fracture Toughness ◽  
Low Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Low Temperatures ◽  
Bend Strength ◽  
Temperature Performance ◽  
Ni Content ◽  
Precision Alloys ◽  
Ni Alloy

Abstract Invar is an Fe-Ni alloy with 36% Ni content that exhibits the lowest expansion of known metals from very low temperatures up to approximately 230 deg C (445 deg F). Invar M93 is a cryogenic Invar with improved weldability. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear and bend strength as well as fracture toughness and fatigue. It also includes information on low temperature performance as well as forming and joining. Filing Code: FE-143. Producer or source: Metalimphy Precision Alloys.

Treatment system response to transient AOX (adsorbable organic halogen) loadings

1997 ◽  
Vol 35 (2-3) ◽  
pp. 85-91
Author(s):  
D. A. Barton ◽  
J. D. Woodruff ◽  
T. M. Bousquet ◽  
A. M. Parrish
Keyword(s):  
Paper Industry ◽  
Model Development ◽  
Operating Conditions ◽  
System Response ◽  
Additional Information ◽  
Organic Halogen ◽  
Aox Removal ◽  
Variable Operating Conditions ◽  
Plant Shutdown

If promulgated as proposed, effluent guidelines for the U.S. pulp and paper industry will impose average monthly and maximum daily numerical limits of discharged AOX (adsorbable organic halogen). At this time, it is unclear whether the maximum-day variability factor used to establish the proposed effluent guidelines will provide sufficient margin for mills to achieve compliance during periods of normal but variable operating conditions within the pulping and bleaching processes. Consequently, additional information is needed to relate transient AOX loadings with final AOX discharges. This paper presents a simplistic dynamic model of AOX decay during treatment. The model consists of hydraulic characterization of an activated sludge process and a first-order decay coefficient for AOX removal. Data for model development were acquired by frequent collection of influent and effluent samples at a bleach kraft mill during a bleach plant shutdown and startup sequence.

scholarly journals Evaporator Optimization of Refrigerator Systems Using Quality Analysis

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 555
Author(s):  
Sangkyung Na ◽  
Sanghun Song ◽  
Seunghyuk Lee ◽  
Jehwan Lee ◽  
Hyun Kim ◽  
...  
Keyword(s):  
Power Consumption ◽  
Operating Time ◽  
Cooling Capacity ◽  
Operating Conditions ◽  
Quality Analysis ◽  
Lubricating Oil ◽  
Optimal Operating ◽  
Compressor Piston ◽  
Refrigerator Temperature ◽  
Visualization Experiments

In this study, evaporator optimization, via both experimental and simulation methods was conducted. To evaluate the evaporator performance, under the optimal system, the compressor operating time and the effects of oil on the refrigerator system were studied. If the temperature of the refrigerator chamber reaches the setting value, the compressor stops working and it leads to the temperature of the refrigerator chamber slowly increasing, due to the heat transfer to the ambient. When the refrigerator temperature is out of the setting range, the compressor works again, and the refrigerator repeats this process until the end of its life. These on/off period can be controlled through the compressor piston movement. To determine the optimal compressor operating conditions, experiments of monthly power consumption were conducted under various compressor working times and the lowest power consumption conditions was determined when the compressor worked continuously. Lubricating oil, the refrigerator system, using oil, also influenced the system performance. To evaluate the effect of oil, oil eliminated and oil systems were compared based on cooling capacity and power consumption. The cooling capacity of the oil eliminated system was 2.6% higher and the power consumption was 3.6% lower than that of the oil system. After determining the optimal operating conditions of the refrigerator system, visualization experiments and simulations were conducted to decide the optimal evaporator and the conventional evaporator size can be reduced by approximately 2.9%.

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