RU2221996C2 - Process measuring thrust force of jet engine installations and bench for its implementation - Google Patents

Abstract

FIELD: testing equipment. SUBSTANCE: process consists in measurement of action of jet engine on primary converter. Action is transferred to primary converter with the help of intermediate member. Action is recorded in pressure chamber where several engines are placed at same time. Cone in which jet engine installation flame is positioned is found in advance and then jet engine installations are so placed that their flame cones do not cross. Then each jet engine installation is switched on in turn, readings of each pickup are recorded in this process. Conclusion on operation of each jet engine installation is made with allowance for errors induced by operation of neighboring jet engine installations. Proposed bench includes support 1, force measuring pickups 2, intermediate member 5 to transfer force linked to recorder. Jet engine installations 4 are positioned in pressure chamber along spiral 7. Force measuring pickups 2 are mounted on support 1 and along spiral 7. EFFECT: expanded functional capabilities. 2 cl, 2 dwg

Description

 When developing and testing various types of propulsion systems, one of the most important characteristics is the characteristic of the thrust of the remote control. The present invention relates to the field of testing jet engines, in particular to the field of methods and devices for determining the thrust of plasma engines, primarily in acceptance tests.

 The greatest difficulty in determining the thrust of a propulsion system (DE) arises due to the fact that the test object in such cases has significant dimensions and weight, and the recorded loads are on the verge of measuring accuracy of the equipment used. The procedure for registering loads is quite trivial and includes placing the test object on a bench with various types of equipment (for example, on various dynamometric platforms), connecting recording equipment (various load meters), starting the load source and recording the effects. For example, A.S. USSR 518652, 459698, 608066, etc.

 Closest to the proposed invention is (prototype) "Method for determining the momentum of the thrust of a rocket engine and a stand for its implementation" RF patent 2091736, cl. G 01 L 5/13. The method for determining the impulse of the thrust of a rocket engine using a primary transducer is to measure the impact of a rocket engine on the primary transducer through a friction clutch. Then determine the impulse of engine thrust according to a formula that takes into account the effect obtained using the primary Converter. The stand itself includes a support, a primary transducer, a longitudinal friction clutch connected to the recorder, which provides the transmission of influence from the engine to the measuring device.

 A significant drawback of both the test methods discussed above and the stands themselves is their low suitability for determining the thrust of electric jet engines (ERE). With a mass of tens of kg, together with the necessary fittings, the engine thrust is several grams. In addition, the propulsion tests themselves should be carried out in a vacuum chamber, since the presence of the atmosphere significantly affects the performance of the propulsion.

 For acceptance tests, as a rule, a batch of remote control is supplied, and testing individually for each remote control leads to a significant cost overrun. Placing well-known stands in a pressure chamber even for testing one remote control is problematic, and installing several stands is impossible in principle. That is, the stand should be small-sized and allow for a fairly simple installation - dismantling. In addition, there should not be any foreign objects in the plasma torch zone, and the remote control torches themselves should not intersect. Thus, not one of the well-known authors of the stands and methods for determining the thrust of jet engines in the acceptance tests of thrust of small propulsion engines is suitable.

 The aim of the invention is the elimination of these disadvantages.

 The proposed method for simultaneously measuring the thrust of jet propulsion systems using a primary transducer is to measure the impact of a rocket engine on the primary transducer, while the transmission of the impact from the platform to the primary transducer is performed using an intermediate element. The claimed method differs in that the exposure is recorded in a pressure chamber, and at the same time several engines are placed in it. In this case, the cone into which the torch of the propulsion system is placed is preliminarily determined, then the propulsion systems are placed so that the cones of the torches do not intersect. Then each propulsion system is subsequently turned on, each sensor readings are recorded during this process, and the conclusion about the operation of each propulsion system is made taking into account the errors introduced by the operation of neighboring propulsion systems.

 A stand for implementing a method for simultaneously measuring thrust of jet propulsion systems comprises a support, a primary transducer connected to an intermediate element recorder for transmitting forces. The stand differs in that the propulsion systems are arranged in a pressure chamber in a spiral. And the location of the propulsion systems on the spiral, their maximum number, as well as the pitch of the spiral are determined by the size of the cone in which the torch of the propulsion system is placed. In addition, force sensors are installed on the support in a spiral, the sensitivity axes of which coincide with the direction of thrust of the propulsion systems or are perpendicular to them. Moreover, the steps of the spirals along which force sensors and propulsion systems are installed are the same.

 The essence of the invention is illustrated by drawings, where figure 1 shows a stand for determining the thrust of jet engines. The stand consists of a support 1 with installed sensors for recording efforts 2. Cable 3 provides fastening of the movable platform. The force from the working remote control 4 is transmitted to the force detection sensors 2 using an intermediate element 5. The sensitivity axes of the force sensors 2 coincide with the thrust direction of the propulsion systems 4 or are perpendicular to them (if the registration of forces is carried out according to the scheme shown in figure 2, where additionally cylindrical hinge 8 and support 9). The location of the propulsion systems in space is carried out in a spiral 6 (shown by a dotted line). The number of remote controls simultaneously installed in the vacuum chamber is determined by the size of the cone 7, into which the torch of the running propulsion system is placed.

 The invention can be explained as follows. When conducting tests to measure the thrust of the electric propulsion, it is necessary to obtain a change in the thrust force over time. For this, various force sensors can be used. During the acceptance tests of the electric propulsion, the registration of forces should be carried out in a vacuum chamber (otherwise the engine will be damaged, and the registered forces will not correspond to the standard operation of the remote control). For acceptance tests usually delivered a batch of remote controls. Testing, in which each remote control is alternately installed in a vacuum chamber, then air is pumped out, efforts are recorded and the remote control is replaced, entails high costs and requires lengthy tests. The location in the vacuum chamber at the same time several rather bulky stands is difficult (due to the limited area of the chambers). Obviously, there should be one stand, providing information retrieval from all remote controls. For a more rational use of the volume of the vacuum chamber, the remote controls are arranged in space in a spiral. The number of engines that can be placed in the chamber is determined by its size and the shape of the flame of the remote control. To arrange the engines in a vacuum chamber at the stage of working out the remote control (according to the results, for example, photographing), a conical surface is built, inside which the engine plume is placed. Further in space these cones are located (for example, using computer simulation), and the permissible number of remote controls is determined for a particular camera. The coincidence of the sensitivity axes of the registration sensors and the thrust vector of the remote control ensures accurate registration of the thrust force.

 The operating time of the remote control with PSI is usually about 30 minutes, but at the same time, mutual influence on the measurement results of the traction force of the remote control is possible. Therefore, each remote control is first turned on for several seconds, and registration is performed by all force sensors. This approach will allow taking into account the mutual influence of the remote control operation on the results of measurements of neighboring remote control (possible electrical interference in the measuring channels).

 The remote control sign on the cable makes it easy to install in the camera. The same pitch of the spirals on which the motors and force sensors are installed provides a horizontal arrangement of the intermediate element.

Practical example
At present, NPO PM is starting to develop a traction measurement scheme with one remote control, and based on the results of these works, a stand will be finally assembled for simultaneously registering the traction force of several remote controls. Installation of the stand will be carried out in a vacuum chamber KVU-400. The working area has a diameter of 5100 mm and a height of 10,000 mm. At the same time, according to preliminary data, eight stationary plasma engines of the M-70, M-100 type with a nominal thrust of 4 and 8 grams, respectively (8 and 16 g when two remote controls are in the same block) can be tested in it. The working pressure in the chamber is ~ 10 ^-6 mm RT. Art. The weight of one remote control unit with highways for supplying xenon is ~ 17.5 kg. For force registration, PS-1-50 power converters are used based on the TKB-6 integrated beam converters with a nominal force of 50 g and a dynamic range of 10 ⁴ . The completion of the stand creation is expected in the fourth quarter of 2001.

Claims (2)

1. The method of measuring the thrust of a jet propulsion system using a primary transducer, which consists in measuring the impact of a rocket engine on the primary transducer, wherein the transmission of the impact from the platform to the primary transducer is performed using an intermediate element, characterized in that the impact is recorded in a pressure chamber, and several engines are placed at the same time, while the cone into which the torch of the propulsion system is placed is pre-determined, then The units are placed in such a way that the cones of the torches do not intersect, then each engine unit is subsequently turned on, each sensor readings are recorded during this process, and the conclusion about the operation of each engine unit is made taking into account the errors introduced by the operation of the neighboring engine units. 2. A bench for implementing a method of measuring thrust of a jet propulsion system, comprising a support, a primary transducer connected to an intermediate element recorder for transmitting forces, characterized in that the propulsion systems are arranged in a pressure chamber in a spiral, where their maximum number and also the pitch of the spiral are determined by the size the cone in which the torch of the propulsion system is placed, in addition, force sensors are installed on the support in a spiral, the sensitivity axes of which coincide with the direction of thrust of the engine installations, or perpendicular to them, and the steps of the spirals along which force sensors and propulsion systems are installed are the same.

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