Simplex Fuel Nozzle In Aircraft Systems: Challenges And Applications

Explain, using diagrams and examples where necessary, the following terms in relation to aircraft systems:

1.Simplex
2.Duplex
3.Triplex
4.Quadruplex
5.Dual-Duplex

Give examples of a system or circuit on an aircraft where each would be used.

Quality of assignment including harvard referencing, spelling, grammar and layout

Introduction to Simplex Fuel Nozzle

The term Simplex in aircraft systems has significantly been used in the turbine engine fuel system.

Simplex fuel nozzle was one of the first types of nozzles to be used in turbine engines, and it was later replaced in most installations with a duplex nozzle, which was giving better atomization at idling and starting speeds. Up to date, the simplex nozzle is still applicable in several facilities in aircrafts. All the simplex nozzles consist of the nozzle tip, a strainer which is made up of a screen of fine-mesh, an insert and support (Atkins, 2017, p. 345).

Gas turbines systems, particularly in the cases of aircraft engines, are greatly exacting their demands for fuel nozzles. That is due to the high velocity which is experienced in the combustion chambers in relation to the size of the combustion apparatus. For the purpose of promoting proper combustion very high levels of fuel, atomization must be achieved (Austin, 2013, p. 254). There are many challenges of attaining consistent good spray and atomization of the fuel. The diagrams below explains the simplex fuel nozzle into details.

The examples where the term simplex has been used in aircraft systems.

The term simplex has been used in the turbine fuel system, where it is used to explain a type of a fuel nozzle.

The term duplex has been widely used in aircraft systems as discussed below:

Aircraft duplex system

Aircraft duplex system refers to a system used for actuating transmitting and feedback the signals between the control centre and the remote portion of an aircraft by the use of standard wires. Operating signals from electrohydraulic valve and signals from a linear varying differential transformer which is used in the monitoring of the valve operations mostly occur in a considerably different frequency spans and they are transferred concurrently on the ordinary wire (Cane, 2014, p. 34). Signal discrimination is usually accomplished by the application of capacitors and inductors which are connected in series and also by use of reliance on the behaviour of a given control components.

This discovery relates directly to the control systems missiles and aircrafts, and it is commonly used in the system which is responsible for transmitting, monitoring and controlling signals within different parts of an aircraft.

To a limited extent, it is conflicting with the considerable attention which has been directed in recent past to the reduction in weight and size of hydraulic and electronic components. For operating and controlling Different portions of an aircraft, that considerable attention has not been focused on a cable system for the purpose of transferring electrical signals between different locations. In some cases is of great bulk and weight than that of the control components. This challenge has been of the recent past been highlighted in the inventions which are geared towards aircrafts are much better and safer (Dalamagkidis, 2014, p. 67).  The main objective is achieving economy of operations.

Challenges of Fuel Atomization in Aircraft Systems

Further a lot of wiring which is encountered in aircrafts introduces a very complex problem regarding the reliability of the aircraft. It is unquestionable that the bigger the number of connecting terminal and connecting lines in a given installation, the more significant are the chances of encountering faults. In a closed loop servo system, this is of great importance since it is considered to be possible (Dillingham, 2012, p. 128). In the case of failure of the response loop, for instance, that an uncontrollable or hard over conditions will be significantly affected. It would be of great importance to have a system with components which are controlled by a remote.

The aircraft duplex system was invented with the main objectives of reducing the additional number of cables within an aircraft installation. That can be achieved by utilizing the common lines mainly for the purpose of transferring signals to and from different control components.

The aircraft duplex system is used as an object to give a system of wiring mainly for the control system which in most cases is reliable than the initial systems which were used. It also provides an economy of bulk and weight.

The duplex system provides an improved version for interconnecting a servo system with a closed loop which comprises a linear variable differential transformer and an electrohydraulic valve which are located at the aircraft electronic bay and the control station (Kempinski, 2015, p. 124). The aircraft duplex system comprises many features which are used in the transmitting of signals from one point of the aircraft to another.

Example where applicable in the aircraft systems.

The term duplex has been used in the control and communication systems of the aircraft. The term has been used in a system to transmit the signals between the control system and the remote area.

Triplex

The term triplex has been widely used in the simulation and modelling of redundancy hybrid auctions system. This triplex system conforms to the future development trends in the electric aircrafts. Triplex redundant hybrid actuation comprises of the traditional servo which is a valve controlled hydraulic actuator, electro-mechanical actuator and an electro-hydrostatic actuator. The operating principles and structure of this system are represented as a mathematical simulation model.

The requirements of reliability and safety are much higher than the ones which were observed initially. To meet the needs of security and safety increasing the number of redundancy is not enough. Dissimilarity in all the redundant is required which is known as hybrid actuation is highly required. In most cases the power-by –wire is the best. Below is a schematic diagram showing the triplex Redundant Hybrid Actuation system.

Duplex System in Aircraft Control

During the modelling of the system, the following are determined to enable come up with a system which works efficiently without any challenge.

The equation for electromotive, torque balance, back electromotive force, load torque, flow control and flow continuity equations (Krieger, 2016, p. 82). For the purpose of reflecting the actual feedback of the system, it is compulsory that the whole system is built in the LMS .in figure 2 the various modes of operation are simulated and analysed.

As a result of physical principles which were much different from the actuators which are in most cases used in the triplex redundant hybrid actuation and the various loads which are in most cases characterised with the uniqueness in the load driving.

Examples where the term duplex has been used in the aircraft system.

The term duplex is used in many aircraft systems such as the aircraft flight control system, fuel and turbine system. In the Aircraft flight control system, the term is used when explaining the fly-by-wire control system which is used in the control of flying aircrafts and helicopters (Langton, 2016, p. 342). In the case of the turbine and fuel system, the term is used to explain a type of fuel nozzle.

The term Quadruplex in aircrafts and Helicopters has significantly been used in the safety and redundancy system. The systems quadruplexed that is four different channels are used to prevent the loss of a signal where there is a failure of either one or two channels.

Increasing the number of redundancy to be four separate lanes of aircraft flight control system would be compulsory if the logic voting was applied and persistent augmentation succeeding two failures was considered essential (Langton, 2011, p. 397).

The Quadruplex system may be small than expected that is due to the complex mechanicals which is involved in this redundancy level, in particular, that is because the rotorcraft does not have many ways of generating regulating moments and forces about a specific axis. A Quadruplex digital aircraft flight control systems which have self-monitoring will only be fitted in aircrafts which have catastrophic failure modes. Based on the MTBF component of 1000 hours, it would be seen that the theoretical probability of total failure will be 7.1X 10 per hour (Valavanis, 2017, p. 45).

All the systems of the aircrafts consist of split lanes of aircraft flight control systems, and they are joined at the central servo jack. Different architecture arranges all the sensor signals to move to all the computers, and the computers are programmed to drive all the actuators. This works to ensure that the system availability is improved that is due to the lane with a failed component can go on to operate by application of signals which are obtained from the surviving components in the remaining lanes (Piegl, 2015, p. 623). Even though the reliability is not altered in any way. Indeed there will be a significant improvement this is because the frequent failures which occur or the frequent failures which are not the same in different lanes will be considered very essential the integrity of the ATCS is questioned (Seabridge, 2012, p. 54).

Aircraft Duplex System: Function and Advantages

The Quadruplex system has been greatly simplified and has been made to ignore the hydraulic/electrical supplies and free sensor package to each line. The actual systems usually are very complicated with the accurate system architecture which varies with the type of an aircraft or the type of AFCS manufacturer formerly a Quadruplex system can still give augmentation following a wide range of many failures but all at a degraded level which is within reduced flight envelope (Rigby, 2013, p. 453). In addition to that optional sensors can be used to in a provision of a synthetical signal when the primary sensor fails.

To assess the aircraft flight control system detailed knowledge for the intended mode of operation and the system architecture is required. Failure modes evaluation and critical analysis are usually carried out to investigate the likely impact of all the possible failures to ensure the soundness of any degraded assessment modes which are typically conducted as flight test program (Moir, 2015, p. 65). Because of the short time which is usually available only the cases which have a more significant possibility of happening will undergo a flight assessment. Many failures can lead to loss of primary sensor in a Quadruplex system such as the vertical gyro.

The example where applicable in the aircraft system.

The term Quadruplex has been mainly used in the flight control system of aircrafts. The Quadruplex Brushless DC motor which is based on a position servo system. The Quadruplex brushless motor which is used in the aircraft control system can offer high power to the motion velocities and weight ratio. The Quadruplex BLDC motor usually provides very high redundancy for the actuator (Piegl, 2015, p. 56).

The term Dual-Duplex in aircraft systems is used t in the fly-by-wire flight control in the main rotor of a helicopter.

Currently, the fly-by-wire control system is widely used in the primary and secondary control of flights of wing aircrafts for the case of rotary aircrafts they make use of dual-duplex electrohydraulic systems in the fly-by-wire flight control system (Mirot, 2017, p. 45).

 The Dual-Duplex fly-by-fly wire system.

This system is based on two systems of hydraulics and also four electrical lanes with the two electrical lanes relating to one hydraulic system. As shown below in concept block diagram.

Each of the four FCCs is tasked to perform closed loop control of the position of the actuator that is achieved by comparing the input command which is established by aircraft control system with the actuator position (Lombardo, 2016, p. 432). The control system of the fly-by-wire electrohydraulic system is clear explained by the block diagram below.

The term dual-duplex has been used in many aircraft systems such as the aircraft flight control system. In this case, the term is used to explain how the two hydraulic systems relate to the four electrical lines.

References

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