Browsing by Author "Verhulst, Tedja"

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    Health monitoring of cavitation erosion on airframe fuel pumps
    (Cranfield University, 2023-09) Verhulst, Tedja; Lawson, Craig; Judt, David
    Aircraft maintenance is a critical aspect of operations that can lead to substantial financial savings if improved. The fuel pump is a vital component of the entire aircraft, ensuring fuel delivery to the engine. Cavitation is common in these pumps, leading to erosion and reducing the pump's remaining useful life. Therefore, the main objective of this work is to develop a viable health monitoring method to diagnose cavitation erosion, where few solutions exist. Initially, a literature review is conducted to identify knowledge gaps and opportunities for technology transfer related to current Health Monitoring (HM) technologies for airborne pumps. Four sensing methods, pressure, flow, current, and temperature sensing, are shortlisted based on their past applications and suitability for an aircraft fuel system installation. A hybrid health monitoring scheme consists of a Computational Fluid Dynamics (CFD) simulation, a model running on Simscape, and an experimental test rig. Live experiments are conducted to validate the simulation methods, enabling the testing of scenarios on a wide range of boundary conditions. The simulations demonstrate strong alignment with the experimental data and successfully distinguish the different levels of erosion. Three out of the four tested sensing methods are sensitive enough to distinguish the different levels of erosion, but each method has its advantages and limitations. Temperature sensing is not useful for health monitoring as the ambient environment strongly influences its results. Despite the success of the developed health monitoring schemes, there is a need for further research and development into more sophisticated health monitoring algorithms before the technologies can be widely implemented on aircraft.
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    ItemOpen Access
    Predicting cavitation erosion on two-stage pumps using CFD
    (IEEE, 2022-10-28) Verhulst, Tedja; Ng, Eddie Yin-Kwee; Chung, Yongmann; Judt, David; Lawson, Craig;
    Cavitation is a common problem that occurs in pumps which reduces its useful life and bring increased operating costs to the user. A study of cavitation erosion on a two-stage centrifugal pump has been carried out using Computational Fluid Dynamics (CFD). Most cavitation studies on pumps have been focused on modelling the severity of cavitation; specifically, on understanding its visual effects and performance penalties. Few works have been carried out to predict the most erosion-sensitive areas inside a pump. The focus of this study is on modelling the permanent damage that would be caused by cavitation and to identify specific areas within the pump which are most susceptible to erosion. The model is first validated against experimental data from another work. Once the simulation has been successfully calibrated, the cavitation simulation is carried out again with the subject pump. Not only does this work extend the findings previous works by predicting cavitation erosion on a two-stage pump, but the pump rotation speed is also varied to observe how the erosion-sensitive areas on the pump changes as a result. A specific focus on the Gray Level Method is carried out to predict the erosion damage on the pump. This technique is chosen as it has been experimentally proven with single-stage radial pumps, using specialized CFD code. It is found that the algorithm used to predict erosion when applied with commercial CFD packages, are useful in distinguishing areas inside the pump which are most vulnerable to erosion damage. The Scherr-Sauer cavitation model coupled with the κ-ω SST turbulence model have been used to run the cavitation simulations.
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    ItemOpen Access
    Review for state-of-the-art health monitoring technologies on airframe fuel pumps
    (Prognostics and Health Management Society, 2022-01-14) Verhulst, Tedja; Judt, David; Lawson, Craig;; Chung, Yongmann; Al-Tayawe, Osama; Ward, Geoff
    Aircraft maintenance is an essential cost borne by the airline. Improving maintenance practices for day-to-day operations can lead to significant financial savings. The benefits of effective maintenance are derived from the avoided costs caused by unexpected breakdowns and from maximising aircraft flight time transporting passengers. The fuel system is a crucial part of the entire aircraft as it ensures delivery of the fuel to the engine and a key component within this system are the fuel pumps. These airborne fuel pumps are classified between the pumps installed in the airframe fuel system and in the engine fuel system. Past works have investigated the performance characteristics of these pumps during flight, however there are no reviews related to the present Health Monitoring (HM) capabilities under flight conditions. HM refers to the field of diagnosing faults or predicting the remaining useful life (RUL) of the pump and the focus of this review is to highlight the HM technologies suitable for aircraft fuel pumps. This is done by first reviewing the technologies and concepts related to HM of fuel pumps. Second a literature review is carried out on pump and motor faults is carried out, drawing on examples from aerospace and other relevant industries. Section 6: Conclusion, discusses the HM technologies have been applied to aerospace fuel pumps and highlights the gaps in capabilities, based on the findings of the literature review carried out in Section 4: Common Faults and Section 5: HM Sensing Methods to suggest future developments in this field. It was found that there is a large scope for development for the HM airframe fuel pumps, based on reviewing the present state of the art. Furthermore, there are no clear strategies formulated by airframe manufacturers and equipment suppliers to test and implement existing HM solutions to operate under flight conditions. This highlights the need to develop HM in this field and a requirement for further research to allow this technology to be a part of routine aircraft.