Patent ID: 8490752
Filing Date: 2013-07-23
Classification: F01D,F05D,G01F,G01N

Abstract:
1. A method for determining volumes of lubricant used in a lubrication system of an aircraft turbofan engine that would be present at selected temperatures in the lubrication system based on measured volumes of the lubricant present in lubricant reservoirs provided in the lubrication system at measured temperatures of the lubricant, such the lubrication system further having lubricant use structures interconnected by passageways to which arrangement entry connections are made from each corresponding lubricant reservoir to allow lubricant in that reservoir to reach the lubricant use structures during operation of the lubrication system and from which arrangement return couplings are made to each corresponding lubricant reservoir to allow the lubricant to return to that reservoir during operation of the the lubrication system, the method comprising: predetermining a fixed volume occurring within the lubricant use structures and passageways of the lubrication system, all entry connections, all return couplings together forming a distribution and use system of the lubrication system and further including in that distribution and use system any variable volume devices connected thereto so that any variable volume additions provided thereby are added to the fixed volume to predetermine a distribution and use system volume at a selected representative temperature; measuring one or more subsequent temperatures of the lubricant at one or more locations in the lubrication system, and measuring any subsequent variable volume additions to the distribution and use system, to determine the subsequent measured representative temperature of the lubrication system; measuring subsequent volumes of the lubricant in all lubricant reservoirs in the lubrication system to provide the subsequent measured lubricant volume; determining densities expected for the lubricant at the selected representative temperature and at the subsequent measured representative temperature; and calculating the subsequent volume of the lubricant that would be in the lubricant reservoirs at the selected temperature as a calculated lubricant volume.