• Energy Research

This volume contains the charts and backup material presented to the Atomic Energy Commission and Air Force on June 14, 1962 concerning General Electric's Nuclear Materials and Propulsion Operation (formerly the Aircraft Nuclear Propulsion Department), during its work on the development of a nuclear power plant for manned aircraft.

Deterioration of axial compressors is in general a major concern in aircraft engine maintenance. Among other effects, roughness in high-pressure compressor reduces the pressure rise and thus efficiency, thereby increasing the specific fuel consumption of an engine. Therefore, it is important to improve the understanding of roughness on compressor blading and their impact on compressor performance. To investigate the surface roughness of rotor blades of a compressors, different stages of an axial high-pressure compressor and a first-stage blisk (BLade–Integrated–dISK) of a regional aircraft engine is measured by a three-dimensional laser scanning microscope. Fundamental types of roughness structures can be identified: impacts in different sizes, depositions as isotropically distributed single elements with steep flanks and anisotropic roughness structures direct approximately normal to the flow direction. To characterise and quantify the roughness structures in more detail, roughness parameters were determined from the measured surfaces. The quantification showed that the roughness height varies through the compressor depending on the stage, position and the blade side. Overall complex roughness structures of different shape, height and size are detected regardless of the type of the blades.

Poor aircraft energy management can lead to unsafe and inefficient operations. Despite their impact on safety and economy, energy management skills are not adequately taught or evaluated in civilian pilot training. This paper 1) addresses the need for better energy management training, 2) provides a conceptual and pedagogical framework for later curriculum development, and 3) suggests key attributes of an effective training program. To make the case, the study uses energy management to link safety and efficiency. It then synthesizes energy principles across disciplines and illustrates how such principles, once simplified, become powerful instructional tools. Finally, it suggests that an integrated, energy-centered, top-down training approach will lead to a better mental model of how the airplane works and, in doing so, to enhanced energy management and decision-making skills for safe and efficient operations.

Measurements during solar particle events with dosemeters flying permanently on-board Concorde are used to develop a semi-empirical model, called SiGLE. The model is intended to calculate, for a given flight plan, the dose equivalent received during a solar particle event observed with ground-based neutron monitors. It is successfully in operation in the SIEVERT computerised system intended to improve monitoring of radiation dose received by aircrews, in application to a European Directive. The semi-empirical model is applied to evaluate, for most exposed routes, the radiation doses corresponding to the GLEs observed since 1942 with ion chambers or neutron monitors. The results for the largest GLEs observed in the past are discussed in terms of radiation risk, and guidelines are suggested concerning possible alerts to the aeroplanes in case of events of exceptional magnitude.

Calculations of fluence-to-effective dose conversion coefficients have typically been limited to the standard irradiation geometries of the human body: anterior-to-posterior (AP), posterior-to-anterior (PA), lateral from the right side to the left side (RLAT), lateral from the left side to the right side (LLAT), rotational around the vertical axis (ROT), and isotropic incidence from all directions (ISO). In order to estimate the doses to air crew members exposed to cosmic radiation, the geometrical conditions of irradiation are usually assumed to be isotropic. However, the assumption of isotropic irradiation is in many cases invalid for the high energy component of the radiation field, which is often peaked in the forward direction. Therefore, it was considered useful to extend the calculations of conversion coefficients to other geometries. New sets of conversion coefficients fluence-to-effective dose are presented for the semi-isotropic irradiation of the human body and for the irradiation from the top. Their application to cosmic ray dosimetry is discussed.

Evaluation of LiF:Mg,Ti thermoluminescence dosemeters (TLDs) according to the high-temperature ratio (HTR) method enables the determination of the dose-average linear energy transfer (LET), the mean quality factor and the dose equivalent in mixed radiation fields of unknown composition. The neutron contribution is assessed by the Extended Pair method calibrated in the CERN-EU High-Energy Reference Field (CERF). The advantages of the small passive detectors as an easy-to-handle monitoring system for in-flight surveillance are demonstrated by measurements on-board north-bound and trans-equatorial flights. The experimental results are compared with calculations by the well-established CARI code.

Microalgae's aquatic, non-edible, highly genetically modifiable nature and fast growth rate are considered ideal for biomass conversion to liquid fuels providing promise for future shortages in fossil fuels and for reducing greenhouse gas and pollutant emissions from combustion. We demonstrate adaptability of PRO/II software by simulating a microalgae photo-bio-reactor and thermolysis with fixed conversion isothermal reactors adding a heat exchanger for thermolysis. We model a cooling tower and gas floatation with zero-duty flash drums adding solids removal for floatation. Properties data are from PRO/II's thermodynamic data manager. Hydrotreating is analyzed within PRO/II's case study option, made subject to Jet B fuel constraints, and we determine an optimal 6.8% bioleum bypass ratio, 230°C hydrotreater temperature, and 20:1 bottoms to overhead distillation ratio. Process economic feasibility occurs if cheap CO2, H2O and nutrient resources are available, along with solar energy and energy from byproduct combustion, and hydrotreater H2 from product reforming.

The spectral distribution of the neutron fluence rate was determined on-board a series of eight trans-atlantic flights between Cologne (Germany) and Washington, DC (USA), using a passive Bonner Sphere spectrometer based on thermoluminescence detectors. Contrary to the commonly applied active systems, the passive instrument facilitates a complete discrimination of gamma ray and charged particle-induced events in the detector count rate. The system was calibrated in the CERN-EU High-Energy Reference Field (CERF). The measured spectra are compared with FLUKA Monte Carlo simulations and show excellent agreement.

Aircrew exposure represents one of the recent subjects of occupational individual dosimetry. Since 1991 many new results have been found; there is however a need to gather further data on this exposure and its variation with geomagnetic position, solar activity and flight route parameters. Since 2001, many individual and six long-term monitoring programmes have been conducted onboard aircraft of Czech Airlines (CSA). In these programmes, a Si-diode spectrometer was fixed in an aircraft. Together with it, passive dosemeters thermoluminescent detector, track-etch based neutron dosemeter linear energy transfer and spectrometer) were exposed. More than 700 regular commercial flights were monitored in this manner. CSA supplied us also with full navigation data, which allowed us to calculate the exposure levels using EPCARD 3.2 and CARI6 codes. Direct experimental readings obtained with the detectors mentioned above were interpreted on the basis of calibrations in on-Earth reference fields and compared with calculated data. A satisfactory correlation between all sets of data was observed.