Investigation of thermal convection and low-frequency microgravity by the DACON sensor aboard the Mir orbital complex

The DACON instrument for studying the convection caused by low frequeucy mi croaccelerations aboard spacecraft is described. The convection sensor serv es as a measuring element of this instrument. This is a cylindrical cavity filled with air, where two crossed differential thermocouples are located. The thermocouple junctions lay on two mutually perpendicular lines parallel to the bases of the cylinder and crossing at its axis. The distances from the junctions to this axis are equal. The lateral surface of the cylinder i s thermally insulated, the difference of temperatures on its bases being ke pt constant. One of the tasks for the sensor is to prepare the data for che cking the, adequacy of mathematical models of fluid convection under weight lessness conditions and for obtaining quantitative characteristics of the m icrogravitational medium. The results of ground-based tests of the DACON in strument and the results of experiments with it aboard the Mir station are presented.