Study of Hybrid Lubrication at the Tooth Contact of a Wormgear Transmission: Part 2—Results and Discussion

1998 ◽  
Vol 120 (1) ◽  
pp. 112-118
Author(s):  
Qin Yuan ◽  
D. C. Sun ◽  
D. E. Brewe
Keyword(s):  
Temperature Distribution ◽  
Film Thickness ◽  
Numerical Solution ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Power Loss ◽  
Oil Film ◽  
Supply Pressure ◽  
Transmission Part

Part 2 begins by describing the numerical solution procedures of the hybrid lubrication problem. Results of the computation are then presented that include the detailed pressure and temperature distribution in the oil film, the required supply pressure for maintaining the prescribed minimum oil film thickness, the fluid friction acting on the worm coil surface, the mass flow rate of supply oil, and the power loss associated with the restrictor flow. The feasibility of the hydrostatically lubricated wormgear transmission is discussed in light of these results.

scholarly journals Investigations of mechanical behavior in gear pump using design of software

2014 ◽  
Vol 3 (4) ◽  
pp. 435
Author(s):  
C. Raghunathan ◽  
C. Manoharan
Keyword(s):  
Film Thickness ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Design Of Experiment ◽  
Gear Pump ◽  
Oil Film ◽  
Taguchi Design Of Experiment ◽  
Face Width ◽  
Crank Angle

This research study focused on the various aspects of tribological phenomenon using design of experiments approach, results are analyzed and compared to evaluate the gear performance. Though lot of research work had been carried out on the hydrodynamic gear under static loads, till date no one consider the parameter say stiffness, damping co-efficient, squeeze film effects and the pressure distribution at various crank angle under dynamic load conditions and its effects on inertia forces of gear pump. It covers sinusoidal load, journal speed, face width and mass flow rate with respect to variations in oil film thickness. Frictional test rig was used to measure the frictional force and oil film thickness at various crank angles for every three minutes at an interval of every 15 degree crank angle. The response surface methodology (RSM) analysis shows appreciable increases in respect of performances in mass flow rate, face width, speed and loading against the Taguchi design of experiment results whereas the film thickness is almost same in both RSM and Taguchi design of experiment results. Particular attention is given in this research exertion to learn how the variation in gear dimensions influences the characteristics of the hydrodynamic gear pump. Keywords: Hydrodynamic Gear Pump, Oil Film Thickness, Mathematical Modeling, Taghuchi and RSM, Eddycurrent Cap Sensor.

Application of Thermal Sensors for Determination of Mass Flow Rate and Velocity of Flow in Pipes of Hermetic Systems

2019 ◽  
Vol 826 ◽  
pp. 117-124
Author(s):  
Yurii Baidak ◽  
Iryna Vereitina
Keyword(s):  
Temperature Distribution ◽  
Mass Flow Rate ◽  
Cross Section ◽  
Correction Factor ◽  
Mass Flow ◽  
Flow Rate ◽  
Thermal Sensors ◽  
Pipe Surface ◽  
Pipe Cross Section

The paper relates to the field of measuring technologies and deals with the enhancement of thermoconvective method when it is applied for the experimental determination of such hydrodynamics indicators as mass flow rate and velocity of flow by their indirect parameters - capacity of the heater and the temperatures obtained from two thermal sensors, provided that they are located on the hermetic piping system surface. The issue of determination of correction factor on heterogeneity of liquid temperature distribution in the pipe cross section depending on pipe diameter and fluid movement velocity was clarified. According to the results of numerical calculations, the dependencies of temperature gradient on the pipe surface and the correction factor on the heterogeneity of the temperature distribution along the pipe cross-section under the heater in the function of the velocity of flow in pipes of different diameters are plotted. These dependencies specify the thermal method of studying the fluid flow in the pipes, simplify the experiment conduction, are useful in processing of the obtained results and can be applied in measuring engineering.

Flashing Flow Mechanisms of HFC-134a and HFC-410a Through Short-Tube Orifices

2011 ◽  
Author(s):  
Kitti Nilpueng ◽  
Somchai Wongwises
Keyword(s):  
Temperature Distribution ◽  
Pressure Distribution ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Operating Conditions ◽  
Evaporator Temperature ◽  
Hfc 134A ◽  
Flow Mechanisms ◽  
Short Tube

In this study, the flow mechanisms of HFC-134a and HFC-410A, including flow pattern, pressure distribution, temperature distribution, and mass flow rate inside short-tube orifice are presented and compared under the same working temperature. The test runs are performed at condenser temperature ranging between 35 and 45°C, evaporator temperature ranging between 2 and 12°C, and degree of subcooling ranging between 1 and 12 °C. The results show that the temperature distribution along the short-tube orifice obtained from HFC-410A is slightly higher than that obtained from HFC-134a. On the other hand, the pressure distribution between both refrigerants shows the large difference. It is also found that the tendency of mass flow rate obtained from HFC-134a almost coincides with those obtained HFC-410A as the operating conditions and short-tube orifice size are varied. However, the average mass flow rate of HFC-134a is slightly lower than that of HFC-410A.

2D Parametric Study Using CFD of a Circulation Control Inlet Guide Vane

2007 ◽  
Author(s):  
H. E. Hill ◽  
W. F. Ng ◽  
P. P. Vlachos ◽  
S. A. Guillot ◽  
D. Car
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Pressure Ratio ◽  
Operating Conditions ◽  
Circulation Control ◽  
Trailing Edge ◽  
Pressure Losses ◽  
Supply Pressure ◽  
Edge Radius

Circulation control inlet guide vanes (IGVs) may provide significant benefits over current IGVs that employ mechanical means for flow turning. This paper presents the results of a two-dimensional computational study on a circulation control IGV that takes advantage of the Coanda effect for flow vectoring. The IGV in this study is an uncambered airfoil that alters circulation around itself by means of a Coanda jet that exhausts along the IGV’s trailing edge surface. The IGV is designed for an axial inlet flow at a Mach number of 0.54 and an exit flow angle of 11 degrees. These conditions were selected to match the operating conditions of the 90% span section of the IGV of the TESCOM compressor rig at the Compressor Aero Research Laboratory (CARL) located at Wright-Patterson AFB, the hardware that is being used as the baseline in this study. The goal of the optimization was to determine the optimal jet height, trailing edge radius, and supply pressure that would meet the design criteria while minimizing the mass flow rate and pressure losses. The optimal geometry that was able to meet the design requirements had a jet height of h/Cn = 0.0057 and a trailing edge Radius R/Cn = 0.16. This geometry needed a jet to inflow total pressure ratio of 1.8 to meet the exit turning angle requirement. At this supply pressure ratio the mass flow rate required by the flow control system was 0.71 percent of the total mass flow rate through the engine. The optimal circulation control IGV had slightly lower pressure losses when compared with a reference cambered IGV.

Modeling on the Effect of Imbalance Burner Pressure and Mass Flow Rate in a Full-Scale Gas Fired Industrial Boiler

2003 ◽  
Author(s):  
Hasril Hasini ◽  
Mohd. Zamri Yusoff ◽  
Kamsani Abdul Majid ◽  
Mohd. Rizal Ramli ◽  
Hamdan Hassan ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Flow Pattern ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Cfd Simulation ◽  
Combustion Process ◽  
General Purpose ◽  
Anticlockwise Direction ◽  
Industrial Boiler

CFD simulation of the combustion process in a 120MW gas fired industrial boiler has been performed, with focus on the flow pattern and temperature distribution at the reheater section in the furnace. The modeling was done using general-purpose CFD software, CFD-ACE+ developed by CFD Research Corporation. The effect of imbalance burner pressure is simulated by varying the mass flow rate of fuel (natural gas) injected at each burner. The simulation result shows good qualitative agreement with practical observation. The flow in the furnace is highly swirling with intense mixing and follows a helical pattern in an anticlockwise direction. Temperature distribution prior to entry to the reheater is significantly higher on the right side of the reheater. As a conclusion, the imbalance nozzles pressure creates uneven mass flow rate of air and fuel, which results in asymmetric flow pattern and temperature distribution at the reheater section.

Assessment of Porous Type Gas Bearings: Measurements of Bearing Performance and Rotor Vibrations

2016 ◽  
Author(s):  
Luis San Andrés ◽  
Travis A. Cable ◽  
Yong Zheng ◽  
Oscar De Santiago ◽  
Drew Devitt
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Load Capacity ◽  
Gas Bearings ◽  
Rotor Spinning ◽  
Supply Pressure ◽  
Seizure Event ◽  
Flow Drag ◽  
Gas Bearing

Gas bearings are an attractive means of load support for rotating machinery due to their low mechanical power losses and dispensing of expensive lubrication systems. A subset of gas bearing technology, porous type gas bearings utilize a porous material as a means of feeding externally pressurized gas (typically air) to the bearing clearance region. When compared to typical orifice type hydrostatic bearings, porous bearings distribute pressurized gas more uniformly into the film clearance, thus resulting in a higher load capacity for similar flow rates [1]. The majority of the literature on porous type gas bearings focuses on the numerical evaluation of cylindrical bushings, yet experimental data on their performance is scant. As a follow up to Ref. [2], the paper presents an analysis of measurements of flow, drag torque and rotordynamic response of a large (100 mm OD, ∼275 N) rotor supported on two tilting pad (five-pad) porous journal bearings (specific load∼19 kPa). Measurements of air mass flow into the bearings, with and without the rotor in place, show that the film clearance offers little restriction. The mass flow rate is proportional to the supply pressure and lead to an estimated permeability coefficient. In operation with various levels of supply pressure and with the rotor spinning to 8 krpm (133 Hz, surface speed ∼42 m/s), several rotordynamic response tests (masses up to 6.9 gram) show the rotor amplitude of synchronous response is proportional to the mass imbalance; hence demonstrating the system is linear. Finally, rotor speed coast down tests from 8 krpm show that the bearings offer little drag friction; and increasing the supply pressure gives to lesser drag. The measurements verify the pair of gas bearings support effectively the rigid rotor with little expense in mass flow rate delivered to them. Most importantly, while operating at 10 krpm with a large added imbalance, the system survived a seizure event with little damage to the rotor and bearings, both restored to a near pristine condition after a simple cleaning procedure.

Parametric Modelling of a Spiral Bevel Gear Using CFD

2010 ◽  
Author(s):  
Thomas Webb ◽  
Carol Eastwick ◽  
Herve´ Morvan
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Power Loss ◽  
Static Pressure ◽  
Bevel Gear ◽  
Spiral Bevel Gear ◽  
Parametric Modelling ◽  
Number Of Teeth ◽  
Spiral Bevel

Initial results investigating windage power loss on a rotating shrouded spiral bevel gear using a parametric solid model and Computational Fluid Dynamics (CFD) are presented. The context behind this study is a desire to use CFD as a tool to investigate heat-to-oil within gas turbine bearing chambers and gearboxes in order to reduce costly rig-based experiments. This paper contains the methodology for creation of the parametric model of a spiral bevel gear in Pro/Engineer, formulation of a mesh in ICEM CFD and the subsequent CFD analysis in Fluent 6.2.26 and 12.0.16. A single tooth segment of a 91 teethed spiral bevel gear is produced with periodic boundaries imposed to reduce computational cost. Validation against experimental results for a single control gear is shown with particularly good correlation between static pressure rise across the face of the gear. Mesh verification is also presented. Using the model to change the module of the gear (effectively the number of teeth), investigations show that windage power loss reduces when the number of teeth increases. Analysis of the static pressure variation throughout the domain shows that all gears tested exhibit a linearly increasing relationship between non-dimensional mass-flow-rate and the pressure drop through the shroud restriction. The control gear was seen to have only a weak increase in static pressure gain across the gear tooth as the mass-flow-rate increases; however, a far larger increase exists for the module cases tested — at comparable mass-flow-rates to the control gear. As the number of teeth increase, the pressure gain across the gear reduces, and vice-versa. It is this difference between the gears that results in dissimilar windage power losses.

scholarly journals Mustafa Ozsipahi, Sertac Cadirci, Hasan Gunes, Husnu Kerpicci, Kemal Sarioglu

2020 ◽  
Vol 7 ◽  
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Internal Surface ◽  
Suction Side ◽  
Oil Viscosity ◽  
Two Phase ◽  
Oil Film ◽  
Lubricant Oil ◽  
Immiscible Mixture

The aim of this study is to numerically investigate theeffects of various parameters on the lubricant (oil)-coolant two phaseflow in the lubrication system of hermetic compressors commonlyused on household refrigerators. Lubrication oil is pumped from thesump through an asymmetrically opened hole on the bottom of thecrankshaft (suction side or inlet) by its rotational motion and climbsas an oil film on the internal surface of the helical channel carved onthe crankshaft surface. This oil film is directed to crankshaft upperexit discharging into the coolant refrigerant and it is used tolubricate the moving components of the compressor including thecylinder piston. The oil forms an immiscible mixture with coolant,thus a two phase flow model using Volume of Fluid (VOF) method isused. Specifically, the mass flow-rate of oil is determined as afunction of the rotational speed, oil viscosity and the submersiondepth of the crankshaft in the oil-sump. With increasing rotationalspeed and submersion depth, the mass flow-rate through thecrankshaft upper exit also increases. With increasing oil viscosity themass flow-rate through the crankshaft upper exit decreases due to theincreased friction.

scholarly journals Effect of Oil Mass Flow Rate on Temperature Profile in Oil Wells

2020 ◽  
Vol 77 (2) ◽  
pp. 23-32
Author(s):  
Abdulhafid M Elfaghi ◽  
Wisam B. Ajaj ◽  
Lukmon Owolabi Afolabi
Keyword(s):  
Temperature Distribution ◽  
Temperature Profile ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Temperature Drop ◽  
Oil Wells ◽  
Oil Well ◽  
Mass Flow Rates ◽  
Design Calculations

In several design calculations including the development of programs to optimize production, engineers and scientists require accurate prediction of temperature drop due to flow in oil wells. The purpose of this research is to create mathematical models to predict the effect of oil mass flow rate on temperature distribution in oil wells. A numerical mathematical model is developed to study the parameters affecting the dynamic and static temperature profiles in oil wells in production and shutting operation. The temperature distribution of the oil from the reservoir to the surface and the temperature distribution in the wall tubing of the oil well and casing, cement sheaths, and surrounding formation is studied. The natural flow of oil wells in Alwahat area located 70 Kilometres south of Marada area east of Libya in the Zaggut field called (6Q1-59) is taken as a study case. In production case, different mass flow rates in winter and summer seasons are studied. The temperature profile in the horizontal direction is estimated at different depths. The Results show that the surface temperature of crude oil increases with the rise in mass flow rate.

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