Multidisciplinary Simulation Platform Research Articles

Characteristic Analysis and Coating Application of the Innovative HVOF System Based on the Digital Model

In view of the poor working conditions, high cost and time-consuming parameter design of the traditional spray process, an innovative HVOF thermal spray system based on the digital model has been established by this study to improve coating performance and optimize scheme design rapidly. In particular, the digital model of the oxygen/kerosene HVOF spray system is designed on the AMESim multidisciplinary simulation platform for the first time, and the engineering prototype has been successfully developed. Thus, an efficient design method based on the digital model was proposed, according to which the spray control parameters such as oxygen and kerosene flow are obtained conveniently under a combustion chamber pressure of 1.0 MPa and 2.0 MPa, respectively. The error between the simulation and experiment results was generally less than 5%, and the dynamic characteristics of the key components in the actual spray system were well predicted, suggesting that the dynamic response time of the system would generally less than 0.7 s. Additionally, the WC-12Co coatings were deposited under the working conditions of W1.0 and W2.0, respectively, the microhardness of the coating increased about 23% and the corresponding volume wear rate decreased about 18%. The results show that the increase of the pressure of the combustion chamber can further improve the coating performance, which also verifies the feasibility and reliability of the design method. It was concluded that the innovative HVOF system based on the digital model is of great theoretical value and application significance for predicting spray process parameters conveniently and providing excellent coating performance.

Multidisciplinary Assessment of the Control of the Propellers of a Pusher Geared Open Rotor—Part II: Impact on Fuel Consumption, Engine Weight, Certification Noise, and NOx Emissions

Due to their high propulsive efficiency, counter-rotating open rotors (CRORs) have the potential to significantly reduce fuel consumption and emissions relative to conventional high bypass ratio turbofans. However, this novel engine architecture presents many design and operational challenges both at engine and aircraft level. The assessment of the impact of the main low-pressure preliminary design and control parameters of CRORs on mission fuel burn, certification noise, and emissions is necessary at preliminary design stages in order to identify optimum design regions. These assessments may also aid the development process when compromises need to be performed as a consequence of design, operational, or regulatory constraints. Part I of this two-part publication presents a novel 0D performance model for counter-rotating propellers (CRPs) allowing an independent definition of the design and operation of each of the propellers. In Part II, the novel CRP model is used to create an engine performance model of a geared open rotor (GOR). This engine model is integrated in a multidisciplinary simulation platform which was used to assess the impact of the control of the propellers, on specific fuel consumption (SFC), engine weight, certification noise, and NOx emission, for a GOR with a 10% clipped rear propeller designed for a 160 PAX and 5700 NM aircraft. The main conclusions of the study are: (1) Minimum SFC control schedules were identified for climb, cruise, and descent (high-rotational speeds for high thrust and low-rotational speeds for low thrust), (2) SFC reductions up to 2% in cruise and 23% in descent can be achieved by using the minimum SFC control. However, the relatively high SFC reductions in descent SFC result in ∼3.5% fuel saving for a 500 NM and ∼0.7% fuel saving for a full range mission, (3) at least 2–3 dB noise reductions for both sideline and flyover can be achieved by reducing the rotational speeds of the propellers at a cost of ∼6% increase of landing and takeoff cycle (LTO) NOx and 10 K increase in turbine entry temperature, (4) approach noise can be reduced by at least 2 dB by reducing CRP rotational speeds with an associated reduction of ∼0.6% in LTO NOx, and (5) the control of the CRP at takeoff has a large impact on differential planetary gearbox (DPGB) weight, but it is almost identical in magnitude and opposite to the change in low-pressure turbine (LPT) and CRP weight. Consequently, the control of the CRP at takeoff has a negligible impact in overall engine weight.

Multidisciplinary Assessment of the Control of the Propellers of a Pusher Geared Open Rotor—Part I: Zero-Dimensional Performance Model for Counter-Rotating Propellers

Due to their high propulsive efficiency, counter-rotating open rotors (CRORs) have the potential to significantly reduce fuel consumption and emissions relative to conventional high bypass ratio turbofans. However, this novel engine architecture presents many design and operational challenges both at engine and aircraft level. The assessment of the impact of the main low-pressure preliminary design and control parameters of CRORs on mission fuel burn, certification noise, and emissions is necessary at preliminary design stages in order to identify optimum design regions. These assessments may also aid the development process when compromises need to be performed as a consequence of design, operational, or regulatory constraints. The required preliminary design simulation tools should ideally be 0D or 1D (for computational purposes) and should capture the impact of the independent variation of the main low-pressure system design and control variables, such as the number of blades, diameter and rotational speed of each propeller, the spacing between the propellers, and the torque ratio (TR) of the gearbox or the counter-rotating turbine (CRT), among others. From a performance point of view, counter-rotating propellers (CRPs) have historically been modeled as single propellers. Such a performance model does not provide the required flexibility for a detailed design and control study. Part I of this two-part publication presents a novel 0D performance model for CRPs allowing an independent definition of the design and operation of each of the propellers. It is based on the classical low-speed performance model for individual propellers, the interactions between them, and a compressibility correction which is applied to both propellers. The proposed model was verified with publicly available wind tunnel test data from NASA and was judged to be suitable for preliminary design studies of geared and direct drive open rotors. The model has to be further verified with high-speed wind tunnel test data of highly loaded propellers, which was not found in the public domain. In Part II, the novel CRP model is used to produce a performance model of a geared open rotor (GOR) engine with a 10% clipped propeller designed for a 160 PAX and 5700 NM aircraft. This engine model is first used to study the impact of the control of the propellers on the engine specific fuel consumption (SFC). Subsequently, it was integrated in a multidisciplinary simulation platform to study the impact of the control of the propellers on engine weight, certification noise, and NOx emission.