Validation of a coupled multibody and TEHL simulation by a piston/cylinder component test rig

Author(s):  
Markus Kroneis ◽  
René Scheerer ◽  
Lars Bobach ◽  
Dirk Bartel

A tribological highly stressed contact in the actuating system of axial piston machines is located between the control piston and the control chamber. This paper presents a new type of component test rig for measuring the frictional force and the gap heights between piston and cylinder. For this purpose, the original system is reduced to the actuator system, whereby the real kinematics and the loading forces are maintained. The axial movement of the control piston and the pressure in the control chamber can be configured individually. The measurement results of different parameter variations are compared with the results of the simulation. The simulation based on a coupled multibody and TEHL simulation with a transient, three-dimensional, thermal elastohydrodynamic contact calculation.

Author(s):  
Markus Kroneis ◽  
René Scheerer ◽  
Lars Bobach ◽  
Dirk Bartel

This paper presents a method for coupling a multibody simulation for the actuator system in axial piston machines in combination with a transient, three-dimensional, thermal elastohydrodynamic contact calculation. For the tribological investigation, the oscillating piston/cylinder contact is focused, whereby a simplified model of the actuator system simulates the loads. The developed method allows the integration of a complex tribological contact simulation under mixed friction conditions into a dynamic multibody simulation based on the Newton–Euler method. It is discussed how the accuracy of the results and the calculation time can be improved by the procedure.


Author(s):  
Dongdong Liu ◽  
Yanyan Chen ◽  
Wei Dai ◽  
Ercang Luo

Abstract As a new type of acoustic-electric conversion method, bi-directional impulse turbine provides great potential for developing large scale and economic thermoacoustic power generators. A test rig for turbine tests in acoustic fields, which are provided through two reciprocating pistons, has been introduced. A three-dimensional numerical model has been used to simulate the whole system. The fundamental characteristics of the turbine in oscillating flow are analyzed. Impact of acoustic field features on the turbine performance has been studied. The results show that the performance is sensitive to the acoustic field. For the test rig, a typical result is that with a shaft power of 187 W, the turbine can reach an efficiency around 32%.


Aerospace ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 172
Author(s):  
Hengtao Shi

Recently, a new type of low-loss variable inlet guide vane (VIGV) was proposed for improving a compressor’s performance under off-design conditions. To provide more information for applications, this work investigated the effect of the Reynolds number and clearance flow on the aerodynamic characteristics of this new type of VIGV. The performance and flow field of two representative airfoils with different chord Reynolds numbers were studied with the widely used commercial software ANSYS CFX after validation was completed. Calculations indicate that, with the decrease in the Reynolds number Rec, the airfoil loss coefficient ω and deviation δ first increase slightly and then entered a high growth rate in a low range of Rec. Afterwards, a detailed boundary-layer analysis was conducted to reveal the flow mechanism for the airfoil performance degradation with a low Reynolds number. For the design point, it is the appearance and extension of the separation region on the rear portion; for the maximum incidence point, it is the increase in the length and height of the separation region on the former portion. The three-dimensional VIGV research confirms the Reynolds number effect on airfoils. Furthermore, the clearance leakage flow forms a strong stream-wise vortex by injection into the mainflow, resulting in a high total-pressure loss and under-turning in the endwall region, which shows the potential benefits of seal treatment.


2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Carlo Alberto Niccolini Marmont Du Haut Champ ◽  
Fabrizio Stefani ◽  
Paolo Silvestri

The aim of the present research is to characterize both experimentally and numerically journal bearings with low radial clearances for rotors in small-scale applications (e.g., microgas turbines); their diameter is in the order of ten millimetres, leading to very small dimensional clearances when the typical relative ones (order of 1/1000) are employed; investigating this particular class of journal bearings under static and dynamic loading conditions represents something unexplored. To this goal, a suitable test rig was designed and the performance of its bearings was investigated under steady load. For the sake of comparison, numerical simulations of the lubrication were also performed by means of a simplified model. The original test rig adopted is a commercial rotor kit (RK), but substantial modifications were carried out in order to allow significant measurements. Indeed, the relative radial clearance of RK4 RK bearings is about 2/100, while it is around 1/1000 in industrial bearings. Therefore, the same original RK bearings are employed in this new test rig, but a new shaft was designed to reduce their original clearance. The new custom shaft allows to study bearing behaviour for different clearances, since it is equipped with interchangeable journals. Experimental data obtained by this test rig are then compared with further results of more sophisticated simulations. They were carried out by means of an in-house developed finite element (FEM) code, suitable for thermoelasto-hydrodynamic (TEHD) analysis of journal bearings both in static and dynamic conditions. In this paper, bearing static performances are studied to assess the reliability of the experimental journal location predictions by comparing them with the ones coming from already validated numerical codes. Such comparisons are presented both for large and small clearance bearings of original and modified RKs, respectively. Good agreement is found only for the modified RK equipped with small clearance bearings (relative radial clearance 8/1000), as expected. In comparison with two-dimensional lubrication analysis, three-dimensional simulation improves prediction of journal location and correlation with experimental results.


2012 ◽  
Vol 424-425 ◽  
pp. 598-602 ◽  
Author(s):  
You Min Wang ◽  
Chun Zhao ◽  
Jian Hua Zhang

In order to improve design performance, shorten development cycles, reduce production cost, we design and research the forklift hydraulic system, developed forklift hydraulic system diagram. Forklift virtual prototype’s 3-D solid modeling is designed by Pro / E three-dimensional software, and imported into the ADAMS environment. Add constraints and drivers exert the control function separately to the tilting cylinder and lifting cylinder, carry on the kinematics simulation. Through the analysis to the compound motion actuation control functional arrangement、the compound motion speed graph、the gate’s tilt angle graph、the tilting cylinder stress graph and the lifting cylinder stress graph, he simulation result indicated: each cylinder design is reasonable, the movement without interference,the reasonable work scope satisfied to the work size request


2013 ◽  
Vol 391 ◽  
pp. 232-236
Author(s):  
Wen Huan Yang ◽  
Hai Xu Chen ◽  
Shuang Xie ◽  
Chun Ren Fang

A new Multi-degree of freedom motor and its establishing of teeth layer parameters have been introduced in the paper, also including application method of database, namely using Quasi-Newton methods to solve the non-linear equations of the new motors magnetic circuit net, formed a refined method for designing and analyzing of motor. The establishment of 3d tooth layer parameters database, is provided for the calculation in the design of the new type motor conveniently.


2020 ◽  
pp. 472-478
Author(s):  
D.V. Fadyushin ◽  
G.Yu. Volkov

А method of geometric calculation of a new type of planetary rotary hydraulic machines (PRGM) with satellite stands is developed. The method includes the steps of: 1) calculation of the initial round-link mechanism; 2) calculation of non-round links of the PRGM with outstretches; 3) construction and integration of three-dimensional design system COMPAS-3D fragments of crenellated crowns corresponding to the phases of abutments and lifting-lowering satellites; 4) correction of the toothed contours to eliminate the phenomenon of mismatch of satellite centers with the points of intersection of the trajectories of these centers in their movement relative to the rotor and stator. PRGM with satellite stands are designed to operate as vacuum pumps, compressors and pneumatic motors.


Sign in / Sign up

Export Citation Format

Share Document