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RISS 인기검색어
- 검색키워드
- 저자 : Hamada Mohamed(하마다 모하메드) (검색결과 2 건)
- 무료
- 기관 내 무료
- 유료
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Effect of Aft-deck Length on the Performance of Serpentine Nozzle
Hamada Mohamed(하마다 모하메드),Changwook Lee(이창욱),Heeju Choi(최희주),Jeekeun Lee(이지근) 대한기계학회 2020 대한기계학회 춘추학술대회 Vol.2020 No.8
Serpentine nozzle has been widely utilized in many types of aircraft to minimize the infrared radiation emitted by high temperature parts and exhaust systems. Annular mixer was used in the infrared suppressor of exhaust system to mix the cold outside air with hot gases from the engine. The most important parameters can evaluate the performance of the nozzle with lobed mixer include mixing effectiveness, pressure loss, and pumping performance. A central plug is used at the exit of the lobed nozzle to penetrate the primary stream in the nozzle. In this study a numerical investigation of flow characteristics of the serpentine nozzle with lobed mixer was conducted. The flow characteristics such as velocity, temperature, pressure of the lobed mixer were studied. The three-dimensional model of the serpentine nozzle was used in the simulations that carried out using Star CCM software. The grid system com-posed of 8,364,993 polyhedral cells. Hot gases enter the nozzle through the core that treated as stagnation inlet at a pressure and temperature of 45023 Pa and 811.8 K, respectively. While, the cold air at pressure and temperature of 48963 Pa and 334.8 K, respectively enters via the bypass that considered as stagnation inlet. The outlet of the nozzle was treated as a pressure outlet subjected to atmospheric pressure and temperature. The nozzle body was considered as adiabatic walls with no-slip boundary conditions. The results showed that the increasing aft-deck decreased the temperature inside the nozzle and at exhausted gases that reduced the infrared temperature.
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Computational study of serpentine nozzle performance with annular mixer
Hamada Mohamed(하마다 모하메드),Changwook Lee(이창욱),Heeju Choi(최희주),Jeekeun Lee(이지근) 대한기계학회 2020 대한기계학회 춘추학술대회 Vol.2020 No.8
The suppression of the infrared radiation emitted from the exhaust system and high temperature walls can increase the survivability of fighter aircraft. Anon-symmetric nozzle such as serpentine nozzle is one method can be used to minimize the infrared radiation. A serpentine nozzle can reduce infrared radiation by 70%. Utilization of aft-deck decreases the external jet length and helps in shielding the high temperature sections of the turbine and engine exhaust nozzle that can reduce the IR radiation by 90%. The appropriate understanding of flow characteristics of a nozzle with aft-deck is important for the design process of the engine exhaust nozzle. To study the effect of aft-deck the flow characteristics were compared to those of nozzle without aft-deck. The simulations were carried out using the STAR CCM+ software. The grid system consists of 8,364,993 polyhedral cells was used in simulations. The bypass where cold air enters was treated as stagnation inlet subjected to pressure and temperature of 48963 Pa and 334.8 K, respectively. Core where hot gases enter, was also considered as stagnation inlet with temperature and pressure of 45023 Pa and 811.8 K, respectively. The outlet of the nozzle was treated as a pressure outlet suspected to the atmospheric temperature of 288 K. The results showed that the presence of aft-deck resulted in a slight increase of pressure along the nozzle length, decreasing the temperature of upper and lower nozzle walls, and reduce the size and length of the external jet that can reduce the infrared radiation. Moreover, the velocity at aft-deck decreased that lead to the reduction of the nozzle noise.
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