High-performance 1×4 - demultiplexer for next-generation all-optical telecommunication systems

In this paper the new 1×4 optical demultiplexer for next-generation all-optical switching systems is proposed. The controlled mirrors are the main elements of this device. The control voltage for this mirror is generated by a rectenna from an optical control signal. In according to operation principle this optical signal enters the system simultaneously with an information signal. The analytical approach of calculation energy losses in the demultiplexer based on the translation matrix method is proposed. And also the analytical method of performance calculation is offered for the first time. First of all, the delay time due the transient mode in the power supply circuit is found. The equivalent electrical scheme of the optical demultiplexer is proposed for the first time. Note that the theoretical results obtained in this work can be used for analysing various controlled optical devices. The numerical calculations in accordance to the presented methods are carried out also.

The Specific Fuel Consumption of Aircraft Engines (TSFC versus PSFC)

From a fundamental consideration of the efficiency (eta = P_out / P_in) it already follows that the power-specific fuel consumption, PSFC or c_P of an aircraft engine should be approximately constant, while c = c_P * V applies to the thrust-specific fuel consumption, TSFC or c in a first approach. Obviously, fuel is consumed already at static thrust (V=0). For this reason the thrust-specific fuel consumption needs an extended approach c = c_a + c_b * V. Breguet's range equation can certainly be described with a constant thrust-specific fuel consumption c, if c is determined for the cruise speed in question. However, this leads to an error if you want to use it to calculate an optimal flight speed in a flight performance calculation. It is recommended (for a first simple consideration) to write Breguet's range equation for jets with a constant power-specific fuel consumption c_P. This then leads to an optimal cruising speed for maximum range at minimum drag (md) V_md instead of 1.316 * V_md as it is determined with the "classic" derivation. For more detailed considerations, the "Herrmann model" should replace the simple equation c = c_a + c_b * V.

CFM56- 7B TAKE-OFF ENGINE PERFORMANCE WITH THRUST 26300 LB AND 24200 LB

As an one of engine manufacturers, CFM produces CFM56-7B with some thrust rating versions to fulfill market demand. In this case, operator has some considerations in choosing engine which is appropriate with the demand. The engine performance is very important to be considered, especially the engine capabilities when it is being maximally operated in takeoff phase.This research discusses about the CFM56-7B engine takeoff performance comparison between 26300 lbs and 24200 lbs thrust rating configuration. By processing Test Cell Result data using formula in Engine Shop Manual - 003, author did a performance calculation to know how much the difference that happened to both of those thrust rating configuration.

Performance calculation and configuration optimization of annular radiator by heat transfer unit simulation and a multi-objective genetic algorithm

A performance calculation method based on heat transfer unit (HTU) simulation is proposed to calculate heat transfer capacity and air-side pressure drop of Annular radiator (AR), which can avoid the problem of a huge amount of grids, and at the same time, ensure the calculation accuracy. Calculation results are compared with experimental data, and the average errors of heat transfer capacity and air-side pressure drop are 11.5%, and 5.9%, respectively, which effectively validates the effectiveness and the reliability of this method. Besides, based on HTU simulation knowledge database, a configuration optimization method of AR using Non-dominated Sorted Genetic Algorithm-II (NSGA-II) is introduced. Number of fins in circumferential direction, number of fins in axial direction, and fin height are chosen as design parameters, and two conflicting optimization objectives include heat transfer capacity maximization and air-side pressure drop minimization. Three optimal structures of AR are obtained, and the optimal results indicate that the heat transfer capacity of the optimal configurations increases by 34.31% on average compared with the original one, while the air-side pressure drop decreases by 24.00% on average, which indicates that this method is feasible and valid and can provide significant guidance for structural design of AR.

Derivation to Calculate Pipe Collapse Performance using a Combined Loading Equivalent Grade Accounting for Axial Stress, Internal Pressure, Bending and Torsion

This paper proposes a new analytical derivation to incorporate bending and torsion into collapse calculation, further pushing the already existing approach of combined loading equivalent grade proposed in API TR 5C3 (2019) Clause 8.4.6 Eq. (42) for axial stress and internal pressure (identical to ISO TR 10400 Clause 8.4.7) used to calculate a differential collapse pressure. This new derivation is also based on Hencky-von Mises maximum distortion criterion. The interest of developing such combined loading equivalent grade is to enable the use of the four collapse types described in Clause 8 i.e., Yield Strength, Plastic, Transition and Elastic. The formulae are adapted to a closed-form equation similar to current Eq. (42), enabling pipe collapse performance calculation. Newly derived formulae are checked against a size governed by yield strength collapse to verify consistency. The restrictions regarding collapse performance under compression are discussed.

3D Simulation Workflow for Performance of Sharp and Worn PDC Drill Bits

This paper describes the development of an improved polycrystalline diamond cutter (PDC) drilling performance simulation in 3D which includes worn cutters. A polygonal mesh model is used to improve the geometric data needed for the drilling performance model calculations. Methods for active face identification have been developed to consistently identify a variety of polygonal face types. The simple wear flat definition used for data input is shown to adequately capture the geometry compared to field worn bit scans and provide valuable insights with active face identification. Drilling performance calculation and results from the calibration to laboratory drilling data and validation to both laboratory and field data are shown. Additionally, including a velocity parameter in the drilling performance model reduced model error.

Collaborative design between architecture and structure of large complex ice shell based on air-ribbed inflatable mold: A case of ice restaurant

In 2019, the ice restaurant at the 21st Harbin Ice and Snow World is one of the representative works of contemporary Chinese ice shell architecture. Through the summary of practical experience of the ice restaurant. The design thinking and practice method of coordination between architecture and structure of large complex ice shell are elaborated in detail. The logic and advantages of air-ribbed inflatable mold construction method, numerical simulation optimization process based on Grasshopper platform and structural performance calculation of ABAQUS platform are included. The feasibility of collaborative design method in the design of ice shell building is proved. It promotes the development of ice shell construction. On the basis, the future development direction is prospected.