scholarly journals Prediction the Performance Rate of Chain Type Trenching Machine

2021 ◽  
Vol 2 (2) ◽  
pp. 390-402
Author(s):  
Mohamed GHONİMY
Keyword(s):  
Mathematical Analysis ◽  
Operating Conditions ◽  
Mathematical Equation ◽  
Actual Performance ◽  
Field Efficiency ◽  
Performance Rate ◽  
Theoretical Performance ◽  
Chain Type

The mathematical analysis for estimating the performance rate "RP" of chain-type trenching machine was studied. The mathematical analysis ended with an equation for this type. This mathematical equation was checked under different operating conditions. The practical study of the performance rate showed that the deviation of the theoretical performance rate from the actual performance rate ranged from -3.4 to +2% only for the 150.7 cm and 120.7 cm trench depth respectively. The machine field efficiency ranged from 46.7 to 57% for the 150.7 cm and 120.7 cm depth respectively. It also showed an increase in machine field efficiency by decreasing the trench depth.

Second-Law Analysis in a Steam Power Plant for Minimization of Avoidable Exergy Destruction

2010 ◽  
Author(s):  
Tapan K. Ray ◽  
Pankaj Ekbote ◽  
Ranjan Ganguly ◽  
Amitava Gupta
Keyword(s):  
Work Performance ◽  
Operating Conditions ◽  
Performance Criteria ◽  
Second Law ◽  
Feed Water ◽  
Exergy Destruction ◽  
Actual Performance ◽  
Time Operation ◽  
Major Equipment ◽  
Cycle Efficiency

Performance analysis of a 500 MWe steam turbine cycle is performed combining the thermodynamic first and second-law constraints to identify the potential avenues for significant enhancement in efficiency. The efficiency of certain plant components, e.g. condenser, feed water heaters etc., is not readily defined in the gamut of the first law, since their output do not involve any thermodynamic work. Performance criteria for such components are defined in a way which can easily be translated to the overall influence of the cycle input and output, and can be used to assess performances under different operating conditions. A performance calculation software has been developed that computes the energy and exergy flows using thermodynamic property values with the real time operation parameters at the terminal points of each system/equipment and evaluates the relevant rational performance parameters for them. Exergy-based analysis of the turbine cycle under different strategic conditions with different degrees of superheat and reheat sprays exhibit the extent of performance deterioration of the major equipment and its impact to the overall cycle efficiency. For example, during a unit operation with attemperation flow, a traditional energy analysis alone would wrongly indicate an improved thermal performance of HP heater 5, since the feed water temperature rise across it increases. However, the actual performance degradation is reflected as an exergy analysis indicates an increased exergy destruction within the HP heater 5 under reheat spray. These results corroborate to the deterioration of overall cycle efficiency and rightly assist operational optimization. The exergy-based analysis is found to offer a more direct tool for evaluating the commercial implication of the off-design operation of an individual component of a turbine cycle. The exergy destruction is also translated in terms of its environmental impact, since the irretrievable loss of useful work eventually leads to thermal pollution. The technique can be effectively used by practicing engineers in order to improve efficiency by reducing the avoidable exergy destruction, directly assisting the saving of energy resources and decreasing environmental pollution.

scholarly journals Managing energy performance in buildings from design to operation using modelling and calibration

2021 ◽  
pp. 014362442110083
Author(s):  
Nishesh Jain ◽  
Esfand Burman ◽  
Dejan Mumovic ◽  
Mike Davies
Keyword(s):  
Best Practice ◽  
Good Practice ◽  
Energy Performance ◽  
Operating Conditions ◽  
Design Stage ◽  
Performance Gap ◽  
Actual Performance ◽  
Simulation Tools ◽  
Calibration Protocol ◽  
Covering Design

To manage the concerns regarding the energy performance gap in buildings, a structured and longitudinal performance assessment of buildings, covering design through to operation, is necessary. Modelling can form an integral part of this process by ensuring that a good practice design stage modelling is followed by an ongoing evaluation of operational stage performance using a robust calibration protocol. In this paper, we demonstrate, via a case study of an office building, how a good practice design stage model can be fine-tuned for operational stage using a new framework that helps validate the causes for deviations of actual performance from design intents. This paper maps the modelling based process of tracking building performance from design to operation, identifying the various types of performance gaps. Further, during the operational stage, the framework provides a systematic way to separate the effect of (i) operating conditions that are driven by the building’s actual function and occupancy as compared with the design assumptions, and (ii) the effect of potential technical issues that cause underperformance. As the identification of issues is based on energy modelling, the process requires use of advanced and well-documented simulation tools. The paper concludes with providing an outline of the software platform requirements needed to generate robust design models and their calibration for operational performance assessments. Practical application The paper’s findings are a useful guide for building industry professionals to manage the performance gap with appropriate accuracy through a robust methodology in an easy to use workflow. The methodological framework to analyse building energy performance in-use links best practice design stage modelling guidance with a robust operational stage investigation. It helps designers, contractors, building managers and other stakeholders with an understanding of procedures to follow to undertake an effective measurement and verification exercise.

Practice Effect on Number Facility Performance

1969 ◽  
Vol 24 (1) ◽  
pp. 43-48 ◽  
Author(s):  
Kragg P. Kysor ◽  
James J. Hart
Keyword(s):  
Practice Effect ◽  
Actual Performance ◽  
Two Samples ◽  
Psychometric Measures ◽  
Individual Scores ◽  
Learning Data ◽  
Theoretical Performance

Equations were fitted to learning data obtained on the Number Facility (NF) subtest of the Repetitive Psychometric Measures. Ss were divided into three groups to increase the correlation between their individual scores and the resulting equations. The equations were derived from the pooled scores of two samples. The theoretical performance of Ss based on a logarthmic function was then compared with the actual performance of a third sample. The amount of variability accounted for by the equations ranged from 53 to 86%.

A 3D Multi-Body Dynamics Model for Chain-Type Continuously Variable Unit

2017 ◽  
Author(s):  
Mohammad A. Hotait ◽  
Avinash Singh
Keyword(s):  
Three Dimensional ◽  
Operating Conditions ◽  
Speed Ratio ◽  
3 Dimensional ◽  
Three Dimensional Representation ◽  
Static Performance ◽  
Torque Capacity ◽  
A Chain ◽  
Multi Body ◽  
Chain Type

This paper presents a new 3-dimensional multi-body dynamic model of a chain-type continuously variable unit (CVU). The modeling requirements and assumptions are presented first. Then, the paper discusses the approaches developed to mathematically represent the chain, pulleys, and their interactions in terms of contact and friction. Three dimensional representation of the chain is given. Actual geometries of the pins and pulleys are captured, including crowning on either member. The model is then used to investigate the effects of different operating conditions, including speed ratio and torque, on the quasi-static performance of a CVU. Several metrics are discussed to characterize the behavior of an example CVU under practical operating conditions; these include torque capacity and the ratio of clamping forces. The predictions presented show the sensitivity of the model to these operating conditions. Finally, trends that describe the CVU quasi-static behavior are explained in context of the parameters studied.

Performance Modeling of Unfired Steam Cycle Using Single and Dual Pressure Once-Through Steam Generator

2011 ◽  
Author(s):  
Emad Hamid ◽  
Mike Newby ◽  
Pericles Pilidis
Keyword(s):  
Power Generation ◽  
Power Plant ◽  
Low Cost ◽  
Combined Cycle ◽  
Operating Conditions ◽  
Low Carbon ◽  
Performance Simulation ◽  
Actual Performance ◽  
Combined Cycle Power Plant ◽  
Steam Cycle

The high thermal efficiency and the use of low carbon content fuel (e.g., natural gas) have made the Combined Cycle Power Plant (CCPP) one of the best choices for power generation due to its benefits associate with low cost and low environmental impact. The performance of Unfired Steam Cycle (USC) as a part of the CCPP has significant impact on the performance of the whole power plant as it provides the CCPP with around one third of the total useful power. An accurate performance simulation of the USC is therefore necessary to analyze the effects of various operating parameters on the performance of combined cycle power plant. In this paper, a performance simulation approach for an unfired steam cycle using single and dual pressure-level of an OTSG is presented. The developed modeling method has been applied to the performance simulation of an existing unfired steam cycle power generation unit installed at Manx Electricity Authority and the results are promising. A comparison between simulated and actual performance at design and off design operating conditions of the same USC has shown a remarkable agreement with errors values below 1%.

Mathematical Modeling and simulation of MED without TVC Applied to Zuara Desalination Plant

2021 ◽  
pp. 1-34
Author(s):  
Ali Muftah ◽  
Hacen Dhahri ◽  
Leila Ghedira ◽  
Mabruk Abugderah
Keyword(s):  
Mathematical Modeling ◽  
Seawater Temperature ◽  
Operating Conditions ◽  
System Behavior ◽  
Desalination Plant ◽  
Mass Flow Rates ◽  
Output Ratio ◽  
Total Productivity ◽  
Model Equations ◽  
Performance Rate

Abstract Mathematical thermodynamic modeling is used in desalination systems to obtain unknown values and predict various properties such as enthalpy or phase equilibrium. These models are useful to understand system behavior. Zuara desalination plant is a multi-effect evaporation plant without vapor pressure (MED) with three total units of 40,000 m3/day. A mathematical modeling of the desalination plant thermal components was performed to simulate and forecast the temperatures, mass flow rates, and the productivity of each cell of steam. The total productivity of the desalination unit and the performance rate in different operating conditions was also found. A Python program was used to solve the model equations. The obtained results show that the productivity of the system and the gain output ratio are directly proportional to seawater temperature and inversely proportional to plant load.

Assessment of classical surface organic loading design equations based on the actual performance of primary and secondary facultative ponds

2010 ◽  
Vol 61 (4) ◽  
pp. 971-977 ◽  
Author(s):  
Sílvia C. Oliveira ◽  
Marcos von Sperling
Keyword(s):  
Performance Evaluation ◽  
Hydraulic Retention Time ◽  
Operating Conditions ◽  
Empirical Equations ◽  
Organic Loading ◽  
Actual Performance ◽  
Loading Rates ◽  
Limit Value ◽  
Classical Design ◽  
Operational Aspects

This article presents results from a performance evaluation of 73 full-scale primary facultative ponds and 37 secondary facultative ponds in Brazil. The data were used to test the applicability of some classical design equations for recommended surface BOD loading rates. The empirical equations proposed by Mara in 1976 and 1987 and the equation developed by McGarry and Pescod in 1970 were evaluated. The loading and hydraulic operating conditions were also evaluated to support the analysis of the influence of the parameters surface BOD loading (Ls) and hydraulic retention time (HRT) on the performance of the ponds. The results showed that the design equations proposed by Mara showed good applicability for primary facultative ponds, representing good indicators of the limit value of loading rates to be applied on the units. But the secondary facultative ponds showed good and poor performances for all loading rates and the best ponds, in general, were not those which followed the design equations recommendation. Finally, the influence of the actual loading conditions on the ponds performance was very small and scattered, indicating that other unquantified design and operational aspects were playing an important role.

An Investigation of Steady and Dynamic Performance of a Small Turbojet Engine

2002 ◽  
Author(s):  
Hsiao-Wei D. Chiang ◽  
Chih-Neng Hsu ◽  
Aling Lai ◽  
Royce Lin
Keyword(s):  
Performance Analysis ◽  
Dynamic Performance ◽  
Design Guidelines ◽  
Operating Conditions ◽  
Actual Performance ◽  
Turbojet Engine ◽  
Acceleration And Deceleration ◽  
Engine Testing ◽  
Compressor Map ◽  
Map Data

An investigation was conducted to perform study of small turbojet engine testing and analysis. This program was mainly to investigate the current steady and dynamic performance of a 12-pound thrust turbojet engine. As a result, we can establish the basis for future small turbojet engine design guidelines. This program involved the bench testing of the small turbojet engine at both design and off-design conditions, in order to establish the baseline performance of the engine. Using the PC based data acquisition system, we will be able to test the engine for both steady and dynamic performance and record data for different operating conditions, especially, during very rapid acceleration and deceleration of the engine at different rates. Also, a compressor map testing was conducted to provide the compressor map data to be used by the performance analysis. With the above testing, this program will establish a useful database for the 12-pound thrust turbojet engine. A performance analysis using GASTURB cycle analysis software was performed for performance prediction of the small turbojet engine for both steady state conditions and dynamic transient conditions. Both performance predictions agreed reasonably well with actual performance of the engine.

The Rolling-Pad Journal Bearing: A Promising Antiwhirl Configuration

1981 ◽  
Vol 23 (3) ◽  
pp. 131-141
Author(s):  
M. Malik ◽  
R. Sinhasan ◽  
D. V. Singh
Keyword(s):  
Journal Bearing ◽  
Dynamic Performance ◽  
Journal Bearings ◽  
Operating Conditions ◽  
Performance Characteristics ◽  
Tilting Pad ◽  
The Comparative Study ◽  
Tilting Pad Journal Bearing ◽  
Tilting Pad Journal Bearings ◽  
Theoretical Performance

The rolling-pad journal bearing is a kinematic variation of the well-known tilting-pad journal bearing. In rolling-pad bearings, the pads, instead of tilting about fixed pivots, roll at their back surfaces on the inside surface of a common sleeve to accommodate changes in the operating conditions of the bearing. This paper presents a comparison of the theoretical performance characteristics of rolling-pad journal bearings with those of tilting-pad journal bearings. The comparative study indicates that the dynamic performance characteristics of the rolling-pad bearing configuration are superior to those of the tilting-pad bearing.

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