scholarly journals Analysis of Windmilling Characteristics for a Twin-Spool Turbofan Engine

1997 ◽  
Author(s):  
Min-Su Choi ◽  
In-Shik Kang ◽  
Jin-Shik Lim ◽  
Yong-Shik Hong
Keyword(s):  
Present Method ◽  
Design Stage ◽  
Limited Data ◽  
Turbofan Engine ◽  
Aerodynamic Performances ◽  
Calculation Results ◽  
Engine Components ◽  
Bypass Ratio ◽  
Good Agreement

The windmilling characteristics of twin-spool, high bypass ratio turbofan engine have been analyzed. This analysis is an extension of the previously reported analysis for a single-spool turbojet engine. As before, the aerodynamic performances of engine components are determined by incorporating the available cascade loss correlations. For a given flight condition, the steady-state windmilling conditions are determined by iteratively balancing the mass flow rate and angular momentum through the two spools. Compared to the turbojet analysis, the new analysis requires determination of bypass ratio and work split between the two spools. Some of the calculation results have been compared against the limited data available for a CF-6 engine, and the two show good agreement. The present method is thus shown to be capable in predicting turbofan engine’s windmilling characteristics during its design stage.

Numerical evaluation of hydrodynamic characteristics of planing hulls by using a hybrid method

2021 ◽  
pp. 147509022199024
Author(s):  
Emre Kahramanoglu ◽  
Silvia Pennino ◽  
Huseyin Yilmaz
Keyword(s):  
Experimental Data ◽  
Hybrid Method ◽  
Design Stage ◽  
Hydrodynamic Characteristics ◽  
Calm Water ◽  
Preliminary Design Stage ◽  
Reduction Function ◽  
Hull Forms ◽  
Good Agreement

The hydrodynamic characteristics of the planing hulls in particular at the planing regime are completely different from the conventional hull forms and the determination of these characteristics is more complicated. In the present study, calm water hydrodynamic characteristics of planing hulls are investigated using a hybrid method. The hybrid method combines the dynamic trim and sinkage from the Zarnick approach with the Savitsky method in order to calculate the total resistance of the planing hull. Since the obtained dynamic trim and sinkage values by using the original Zarnick approach are not in good agreement with experimental data, an improvement is applied to the hybrid method using a reduction function proposed by Garme. The numerical results obtained by the hybrid and improved hybrid method are compared with each other and available experimental data. The results indicate that the improved hybrid method gives better results compared to the hybrid method, especially for the dynamic trim and resistance. Although the results have some discrepancies with experimental data in terms of resistance, trim and sinkage, the improved hybrid method becomes appealing particularly for the preliminary design stage of the planing hulls.

Prediction of Solid-Liquid Interface Stability and Dendritic Growth in Multi-Component Alloys with Calphad Method

2005 ◽  
Vol 475-479 ◽  
pp. 2721-2724
Author(s):  
Rui Jie Zhang ◽  
Zhi He ◽  
Wan Qi Jie
Keyword(s):  
Experimental Data ◽  
Present Method ◽  
Dendritic Growth ◽  
Calphad Method ◽  
Liquid Interface ◽  
Interface Stability ◽  
Calculation Results ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Good Agreement

A method to predict the solid-liquid interface stability and the constrained dendrite growth of multi-component alloys was developed based on the Calphad method. The method was applied to several industrial Al-Si-Mg alloys, and the predicted results were compared with some former experimental data. The good agreement between the calculation results and the experimental data demonstrates the superiority of the present method to the classical one based on constant parameter assumptions.

Thrust Reverser for a Mixed Exhaust High Bypass Ratio Turbofan Engine and its Effect on Aircraft and Engine Performance

2012 ◽  
Author(s):  
Tashfeen Mahmood ◽  
Anthony Jackson ◽  
Syed H. Rizvi ◽  
Pericles Pilidis ◽  
Mark Savill ◽  
...  
Keyword(s):  
Engine Performance ◽  
Engine Exhaust ◽  
Turbofan Engine ◽  
The Public ◽  
Engine Model ◽  
Turbine Performance ◽  
Lp Turbine ◽  
Engine Components ◽  
Thrust Reverser ◽  
Bypass Ratio

This paper discusses thrust reverser techniques for a mixed exhaust high bypass ratio turbofan engine and its effect on aircraft and engine performance. The turbofan engine chosen for this study was CUTS_TF (Cranfield University Three Spool Turbofan) which is similar to Rolls-Royce TRENT 772 engine and the information available for this engine in the public domain is used for the engine performance analysis along with the Gas Turbine Performance Software, GasTurb 10. The CUTEA (Cranfield University Twin Engine Aircraft) which is similar to the Airbus A330 is used along side with the engine model for the thrust reverser performance calculations. The aim of this research paper is to investigate the effects on mixed exhaust engine performance due to the pivoting door type thrust reverser deployment. The paper looks into the engine off-design performance characteristics and how the engine components get affected when the thrust reverser come into operation. This includes the changes into the operating point of fan, IP compressor, HP compressor, HP turbine, IP turbine, LP turbine and the engine exhaust nozzle. Also, the reverser deployment effect on aircraft, deceleration time and landing distances are discussed.

Gas Chromatographic Determination of Incurred Dimetridazole Residues in Swine Tissues

1990 ◽  
Vol 73 (5) ◽  
pp. 702-704 ◽  
Author(s):  
David R Newkirk ◽  
Herbert F Righter ◽  
Frank J Schenck ◽  
Joseph L Okrasinski ◽  
Charlie J Barnes
Keyword(s):  
Present Method ◽  
Chromatographic Method ◽  
Chromatographic Determination ◽  
Polarographic Method ◽  
Limited Data ◽  
Withdrawal Time ◽  
Gas Chromatographic Method ◽  
Hydroxy Metabolite

Abstract A gas chromatographic method for determination of 2-hydroxymethyl- 1-methyl-5-nltrolmldazole (DMZOH), the hydroxy metabolite of dimetridazole, in swine muscle has been developed. The method uses cleanup steps similar to those of an earlier polarographic method. The present method Is capable of quantltatlng levels as low as 2 ppb and detecting less than 1 ppb. Recoveries from 30 control tissues spiked at 1,2, or 4 ppb averaged 80.4%. Performance of the method In Incurred tissue was documented and limited data on the depletion of the metabolite In muscle were generated. The muscle of swine given 150 ppm dimetridazole In feed for 14 days contained less than 1 ppb DMZOH at 12 h withdrawal time.

Numerical Prediction of the Influence of Thrust Reverser on Aeroengine’s Aerodynamic Stability

2016 ◽  
Vol 0 (0) ◽  
Author(s):  
Wang Zhiqiang ◽  
Shen Xigang ◽  
Hu Jun ◽  
Gao Xiang ◽  
Liu Liping
Keyword(s):  
Stability Analysis ◽  
Cfd Simulation ◽  
Weak Link ◽  
Flow Distortion ◽  
Aerodynamic Stability ◽  
Turbofan Engine ◽  
Calculation Results ◽  
Engine Stability ◽  
Thrust Reverser ◽  
Bypass Ratio

AbstractA numerical method was developed to predict the aerodynamic stability of a high bypass ratio turbofan engine, at the landing stage of a large transport aircraft, when the thrust reverser was deployed. 3D CFD simulation and 2D aeroengine aerodynamic stability analysis code were performed in this work, the former is to achieve distortion coefficient for the analysis of engine stability. The 3D CFD simulation was divided into two steps, the single engine calculation and the integrated aircraft and engine calculation. Results of the CFD simulation show that with the decreasing of relative wind Mach number, the engine inlet will suffer more severe flow distortion. The total pressure and total temperature distortion coefficients at the inlet of the engines were obtained from the results of the numerical simulation. Then an aeroengine aerodynamic stability analysis program was used to quantitatively analyze the aerodynamic stability of the high bypass ratio turbofan engine. The results of the stability analysis show that the engine can work stably, when the reverser flow is re-ingested. But the anti-distortion ability of the booster is weaker than that of the fan and high pressure compressor. It is a weak link of engine stability.

Influence of Turbine Blade Cooling Efficiency on Turbofan Engine Performance

2013 ◽  
Vol 444-445 ◽  
pp. 1272-1276
Author(s):  
Li Ya Zhu ◽  
Qin Huang
Keyword(s):  
Turbine Blade ◽  
Large Scale ◽  
Pressure Ratio ◽  
Engine Performance ◽  
Cooling Efficiency ◽  
Turbofan Engine ◽  
Turbine Blade Cooling ◽  
Blade Cooling ◽  
Calculation Results ◽  
Bypass Ratio

On the basis of a performance emulation model of turbofan engine, a relation curve was first employed to fix the efficiency of compression components. With the turbine blade cooling efficiency being a restriction, an optimization algorithm was developed on the premise that engine cycle parameters match. The calculation results show that when the turbine blade cooling efficiency was improved at a fixed bypass ratio, the engine overall pressure ratio corresponding to the lowest specific fuel consumption (sfc) grows on a large scale, while the lowest sfc slightly drops and the specific thrust significantly boosts.

Determination of Plasminogen in Human Plasma by the Lysis Time Method

1966 ◽  
Vol 16 (01/02) ◽  
pp. 001-017 ◽  
Author(s):  
W Berg ◽  
K Korsan-Bengtsen ◽  
J Ygge
Keyword(s):  
Human Plasma ◽  
Present Method ◽  
Blood Donors ◽  
Fibrinogen Concentration ◽  
Plasmin Activity ◽  
Time System ◽  
Lysis Time ◽  
High Dilutions ◽  
Single Determination

SummaryA one-stage lysis time system containing fibrinogen, streptokinase, thrombin, and a known, small amount of plasminogen was used to determine plasminogen in plasma.The known amount of plasminogen was added to the system in order to keep the lysis times relatively short when a highly diluted plasma was tested. High dilutions of plasma were used to reduce the influence of the plasma inhibitors.The calculation of the plasminogen concentration was made on the basis of the correlation: “plasminogen = fibrinogen/lysis time” which was valid in the system. The method allowed determination of plasminogen in plasma with varying fibrinogen concentrations, as the fibrinogen concentration in plasma was considered in the calculation.The presence of “spontaneous” plasmin activity in the plasma did not influence the plasminogen determination. Estimated by this method, the plasminogen content in plasma from 32 blood donors aged 25-45 years was 13.1 ±2.4 casein u/ml. The error of a single determination was 0.3 casein u/ml. The plasminogen content in plasma, determined with the present method, is about 3-4 times higher than the content found when a caseinolytic method is used.

COMPARATIVE ACTION OF VARIOUS OESTROGENIC COMPOUNDS ON MOUSE VAGINAL SIALIC ACIDS (II)

1969 ◽  
Vol 62 (4) ◽  
pp. 663-670 ◽  
Author(s):  
Lars Carlborg
Keyword(s):  
Sialic Acid ◽  
Response Curve ◽  
Sialic Acids ◽  
Clear Cut ◽  
Suitable Parameter ◽  
Sufficient Degree ◽  
Comparative Action ◽  
Relative Potencies ◽  
Good Agreement

ABSTRACT Oestrogens administered in lower doses than necessary to induce full cornification of the mouse vagina induce mucification. It was shown previously that the degree of mucification could be estimated by quantitative determination of sialic acids. A suitable parameter for oestrogen assay was the measurement of vaginal sialic acid concentration which exhibited a clear cut dose response curve. Eleven assays of various oestrogens were performed with this method. Their estimated relative potencies were in good agreement with other routine oestrogen assays. A statistically sufficient degree of precision was found. The sensitivity was of the same order, or slightly higher, than the Allen-Doisy test.

An Automated Method for the Determination of Serum Calcium with Glyoxal Bis (2-Hydroxyanil)

1967 ◽  
Vol 13 (6) ◽  
pp. 515-520 ◽  
Author(s):  
Genevieve Farese ◽  
Janice L Schmidt ◽  
Milton Mager
Keyword(s):  
Serum Calcium ◽  
Automated Analysis ◽  
Automated Method ◽  
Good Agreement

Abstract A completely automated analysis is described for the determination of serum calcium with glyoxal bis (2-hydroxyanil) solution (GBHA). The method is simple and precise, and the data obtained are in good agreement with results obtained by the manual GBHA procedure.

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