Overall Efficiency Evaluation of a Hydraulic Pump With External Drainage Through Temperature Measurements

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Paolo Casoli ◽  
Federico Campanini ◽  
Andrea Bedotti ◽  
Mirko Pastori ◽  
Antonio Lettini
Keyword(s):  
Health Management ◽  
Research Field ◽  
Operating Conditions ◽  
Thermodynamic Method ◽  
External Drainage ◽  
Flow Meters ◽  
Swash Plate ◽  
Hydraulic Machines ◽  
Overall Efficiency ◽  
Axial Piston

In the recent years, industries have been working on the online condition monitoring of systems and components in order to definitely abandon the time-based maintenance and switch efficiently to a condition-based maintenance. Therefore, the research field related to prognostics and health management (PHM) has been gaining more and more importance. In the field of hydraulic pumps and motors, the overall efficiency is an important parameter to monitor and the thermodynamic method has historically been proposed for the online evaluation of this parameter for hydraulic machines without external drainage. Indeed, for this kind of machines, the thermodynamic method allows the evaluation of the overall efficiency by measuring only the temperatures and the pressures at the suction and the delivery ports, thus avoiding the use of cumbersome and expensive sensors, such as flow meters and torque sensors. This paper investigates the use of the thermodynamic method for hydraulic machines with external drainage. The case study of a swash-plate type axial-piston pump is considered. In this first part of the project, the objective was to validate the proposed thermodynamic method by comparing its results with the ones obtained through the mechanical, therefore an extensive experimental activity was carried out and two flow meters were used to measure the drainage and the delivery flow rates. The pump was tested in different operating conditions and the uncertainty related to the overall efficiency was calculated accurately in order to compare the two approaches properly.

Condition Monitoring Based on Thermodynamic Efficiency Method for an Axial Piston Pump

2018 ◽  
Author(s):  
Andrea Bedotti ◽  
Mirko Pastori ◽  
Antonio Lettini ◽  
Paolo Casoli
Keyword(s):  
Fault Detection ◽  
Operating Conditions ◽  
Piston Pump ◽  
Thermodynamic Method ◽  
Thermodynamic Efficiency ◽  
Health State ◽  
Axial Piston Pump ◽  
Flow Rates ◽  
Overall Efficiency ◽  
Axial Piston

In the last years, the interest in the field of Prognostics and Health Management (PHM) has been growing in many industrial fields. The objective of PHM is to switch from a time-based (scheduled) maintenance to a predictive maintenance with advantages in terms of reliability and safety. This paper presents the thermodynamic method for the fault detection of an axial piston pump which is a critical component in many hydraulic systems; the method was developed for the evaluation of the overall efficiency which is an important parameter to monitor the machine health state. Through the measurements of temperatures and pressures at suction and delivery ports the method allows to calculate the efficiency avoiding the use of costly sensors, such as speed and torque sensors. The paper investigates the possibility of utilizing the pump overall efficiency evaluated through the thermodynamic method as a reliable parameter for the fault detection. The machine under study is a variable displacement axial-piston pump with external drainage equipped with a load sensing regulator. The thermodynamic method was already validated in a previous work by comparing it with the standard approach, based on the direct measurement of the mechanical power. The proposed method requires the measurement of the delivery and drain flow rates involving the use of expensive flowmeters which could prevent its usage in online applications; this limit should be overcome with the development of low-cost solutions for flow rate measurements. A preliminary investigation of the pump failure modes was conducted to identify the most important faults which need to be considered. An experimental campaign was carried out on a laboratory test bench with the pump in the flawless state and in faulty states. The faulty states were realized by introducing components with artificial faults into the pump. The pump was accurately instrumented to monitor all the main variables, i.e. pressures, temperatures, flow rates, swash plate angle and shaft torque and speed. Different operating conditions were considered and each test was repeated several times in order to acquire a suitable population to verify the repeatability of the data. The experiments demonstrate the method capability of detecting some but not all of the incipient faults tested in steady-state conditions as a consequence of temperature variations which have the most important influence on efficiency estimation. Future works will include the development of innovative solutions to measure flow-rates and the testing of other faults to further verify the reliability of the method.

New Swash Plate Damping Model for Hydraulic Axial-Piston Pump

1999 ◽  
Vol 123 (3) ◽  
pp. 463-470 ◽  
Author(s):  
X. Zhang ◽  
J. Cho ◽  
S. S. Nair ◽  
N. D. Manring
Keyword(s):  
Open Loop ◽  
Operating Conditions ◽  
Reduced Order Model ◽  
Piston Pump ◽  
Axial Piston Pump ◽  
Order Model ◽  
Nonlinear Simulation ◽  
Reduced Order ◽  
Swash Plate ◽  
Axial Piston

A new, open-loop, reduced order model is proposed for the swash plate dynamics of an axial piston pump. The difference from previous reduced order models is the modeling of a damping mechanism not reported previously in the literature. An analytical expression for the damping mechanism is derived. The proposed reduced order model is validated by comparing with a complete nonlinear simulation of the pump dynamics over the entire range of operating conditions.

Designing a Control and Containment Device for Cradle-Mounted, Axial-Actuated Swash Plates

2002 ◽  
Vol 124 (3) ◽  
pp. 456-464 ◽  
Author(s):  
Noah D. Manring
Keyword(s):  
High Pressure ◽  
Closed Form ◽  
High Speed ◽  
Control Device ◽  
Operating Conditions ◽  
Axial Piston Pumps ◽  
Swash Plate ◽  
Proper Design ◽  
Critical Components ◽  
Axial Piston

Many axial-piston pumps utilize a swash plate for regulating discharge flow. In this research, the required control and containment forces are examined for a cradle-mounted, axial-actuated swash plate. These forces are described in closed-form for providing the designer with information that is necessary for sizing these critical components within the pump. In this research, it is shown that a proper design of the control device may be used to load the cradle bearings equally during high-pressure operation. While previous research has shown that a transverse-actuated swash plate will tend to dislocate itself from the cradle during high speed and low pressure operation, this research shows that an axial-actuated swash-plate tends to keep the swash-plate well seated within the cradle during all operating conditions. The information presented here is generalized for typical characteristics of swash plates that are used within the industry and is therefore useful for analyzing existing designs as well as new ones.

Predicting the Required Slipper Hold-Down Force Within an Axial-Piston Swash-Plate Type Hydrostatic Pump

2001 ◽  
Author(s):  
Noah D. Manring
Keyword(s):  
Theoretical Calculations ◽  
A Priori ◽  
Operating Conditions ◽  
Design Parameters ◽  
A Posteriori ◽  
Axial Piston Pump ◽  
Pump Design ◽  
Swash Plate ◽  
Axial Piston ◽  
Plate Type

Abstract The objectives of this research are to determine the physical contributors that tend to separate the slippers from the swash plate within an axial-piston pump. Upon determining these contributors, the hold-down force that is required for maintaining contact between the slippers and the swash plate is determined. This force is then expressed in terms of pump design-parameters and operating conditions. Physically inspecting six industrial pumps and measuring the theoretical calculations against the a-posteriori results of successful pump designs validates the analytical results of this research. By confirming the analysis of this research, an a-priori approach is recommended for adequately specifying the required spring load for the slipper hold-down mechanism.

A CFD Approach for the Simulation of an Entire Swash-Plate Axial Piston Pump Under Dynamic Operating Conditions

2020 ◽  
Author(s):  
Massimo Milani ◽  
Luca Montorsi ◽  
Gabriele Muzzioli ◽  
Andrea Lucchi
Keyword(s):  
Fluid Dynamic ◽  
Operating Conditions ◽  
Piston Pump ◽  
Axial Piston Pump ◽  
Real Component ◽  
The Real ◽  
Flow Ripple ◽  
Swash Plate ◽  
Sliding Interfaces ◽  
Axial Piston

Abstract The paper proposes a CFD approach for the simulation of a swash-plate axial piston pump including the full 3D geometry of the real component. Different meshing techniques are integrated in order to reproduce all the internal motions of the pump. The overset mesh procedure is used to simulate the dynamic evolution in regions’ shape and the variable orientation between parts in the piston-slipper ball joints while the alternating motion of the piston is accounted for by sliding interfaces with the neighboring regions. The multiple dynamics of the different moving elements are implemented in terms of superposing motions in order to reproduce the real position time histories as a function of the rotational speed and the swash plate inclination angle. The proposed numerical model includes all the leakages that characterize the coupling of the many components of the pump and nominal values are assumed (i.e. 10μm) throughout the entire simulation. A pressure-dependent fluid density approach is adopted to improve the performance prediction of the pump under real operating conditions. Moreover, the turbulent behavior of the flow is addressed by means of the two equation k-omega SST model. Therefore the proposed modeling approach highlights the capabilities to address any type of swash-plate axial piston pump in order to simulate the entire machine under dynamic operations; the numerical results are discussed in terms of flow ripple, pressure distribution and fluid-dynamic forces.

scholarly journals Transfer Learning for Prognostics and Health Management (PHM) of Marine Air Compressors

2021 ◽  
Vol 9 (1) ◽  
pp. 47
Author(s):  
Magnus Gribbestad ◽  
Muhammad Umair Hassan ◽  
Ibrahim A. Hameed
Keyword(s):  
Transfer Learning ◽  
Data Transfer ◽  
Health Management ◽  
Correct Diagnosis ◽  
Vital Role ◽  
Research Field ◽  
Remaining Useful Life ◽  
Prognostic Models ◽  
Classification Problems ◽  
Air Compressors

Prognostics is an engineering discipline focused on predicting the time at which a system or a component will no longer perform its intended function. Due to the requirements of system safety and reliability, the correct diagnosis or prognosis of abnormal condition plays a vital role in the maintenance of industrial systems. It is expected that new requirements in regard to autonomous ships will push suppliers of maritime equipment to provide more insight into the conditions of their systems. One of the stated challenges with these systems is having enough run-to-failure examples to build accurate-enough prognostic models. Due to the scarcity of enough reliable data, transfer learning is established as a successful approach to improve and reduce the need to labelled examples. Transfer learning has shown excellent capabilities in image classification problems. Little work has been done to explore and exploit the use of transfer learning in prognostics. In this paper, various deep learning models are used to predict the remaining useful life (RUL) of air compressors. Here, transfer learning is applied by building a separate prognostics model trained on turbofan engines. It has been found that several of the explored transfer learning architectures were able to improve the predictions on air compressors. The research results suggest transfer learning as a promising research field towards more accurate and reliable prognostics.

Improving the Volumetric Efficiency of the Axial Piston Pump

2012 ◽  
Vol 134 (11) ◽  
Author(s):  
Shu Wang
Keyword(s):  
Operating Conditions ◽  
Volumetric Efficiency ◽  
Valve Plate ◽  
Piston Pump ◽  
Efficient Design ◽  
Axial Piston Pumps ◽  
Definition Of ◽  
Engineering Practices ◽  
First Time ◽  
Axial Piston

The volumetric efficiency is one of the most important aspects of system performance in the design of axial piston pumps. From the standpoint of engineering practices, the geometric complexities of the valve plate (VP) and its multiple interactions with pump dynamics pose difficult obstacles for optimization of the design. This research uses the significant concept of pressure carryover to develop the mathematical relationship between the geometry of the valve plate and the volumetric efficiency of the piston pump. For the first time, the resulting expression presents the theoretical considerations of the fluid operating conditions, the efficiency of axial piston pumps, and the valve plate designs. New terminology, such as discrepancy of pressure carryover (DPC) and carryover cross-porting (CoCp), is introduced to explain the fundamental principles. The important results derived from this study can provide clear recommendations for the definition of the geometries required to achieve an efficient design, especially for the valve plate timings. The theoretical results are validated by simulations and experiments conducted by testing multiple valve plates under various operating conditions.

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