Shock attenuation in a ‘gradual’ area expansion

1973 ◽  
Vol 60 (2) ◽  
pp. 209-223 ◽  
Author(s):  
M. A. Nettleton

The effect of the angle of divergence ϕ, the magnitude of the area ratio A21 and the specific-heat ratio of the gas γ on the attenuation of a shock in a two-dimensional area expansion has been experimentally determined. The results are compared with current theories relating shock strength and area ratio. At some distance from the expansion the change in shock strength, for shocks with strengths up to 10, is predicted reasonably accurately by an analysis of Chisnell (1957). Close to the area change surprisingly strong shocks were observed. This is shown to result from the diffracted shock undergoing a Mach reflexion at the end of the expansion.

2014 ◽  
Vol 590 ◽  
pp. 546-550
Author(s):  
Zhi Qiang Fan ◽  
Hai Bo Yang ◽  
Fei Zhao ◽  
Rong Zhu ◽  
Dong Bai Sun

The practical requirements of the project the nozzle entrance temperature is high, the gas specific heat ratio varies greatly, so it must consider the specific heat ratio change impact on two-dimensional nozzle contour design. Divided into consideration specific heat ratio change and not consider two kinds of scheme design of 1.4Ma nozzle profile and build the model using the arc line method, numerical simulation is carried out through the CFD software Fluent, analysis of two kinds of design scheme comparison. The results show that, in the supersonic nozzle at low Maher numbers, two schemes of nozzle design profile similarity, parameters change little flow tube, export the Maher number and the flow quality can meet the design requirements, proof of specific heat ratio has little effect on the design results in the design of the nozzle under the condition of low Maher number.


AIAA Journal ◽  
1980 ◽  
Vol 18 (9) ◽  
pp. 1025-1026 ◽  
Author(s):  
Kemal Tuzla ◽  
David A. Russell ◽  
John C. Wai

1978 ◽  
Vol 56 (10) ◽  
pp. 1390-1394
Author(s):  
K. P. Srivastava

An extensive numerical study on specific heat at constant volume (Cv) for ordered and isotopically disordered lattices has been made. Cv at various temperatures for ordered and disordered linear and two-dimensional lattices have been compared and no appreciable difference in Cv between these two structures has been observed. Effect of concentration of light atoms on Cv for three-dimensional isotopically disordered lattices has also been shown.In spite of taking next-nearest-neighbour interaction into account, no substantial change in Cv between the ordered and isotopically disordered linear lattices has been found. It is shown that the low lying modes contribute substantially at low temperatures.


1998 ◽  
Vol 259 (3-4) ◽  
pp. 388-396 ◽  
Author(s):  
W. Selke ◽  
L.N. Shchur ◽  
O.A. Vasilyev

Author(s):  
Ragnhild E. Ulfsnes ◽  
Olav Bolland ◽  
Kristin Jordal

One of the concepts proposed for capture of CO2 in power production from gaseous fossil fuels is the semi-closed O2/CO2 gas turbine cycle. The semi-closed O2/CO2 gas turbine cycle has a near to stoichiometric combustion with oxygen, producing CO2 and water vapor as the combustion products. The water vapor is condensed and removed from the process, the remaining gas, primarily CO2, is mainly recycled to keep turbine inlet temperature at a permissible level. A model for predicting transient behavior of the semi-closed O2/CO2 gas turbine cycle is presented. The model is implemented in the simulation tool gPROMS (Process System Enterprise Ltd.), and simulations are performed to investigate two different issues. The first issue is to see how different cycle performance variables interact during transient behavior; the second is to investigate how cycle calculations are affected when including the gas constant and the specific heat ratio in compressor characteristics. The simulations show that the near to stoichiometric combustion and the working fluid recycle introduce a high interaction between the different cycle components and variables. This makes it very difficult to analytically predict the cycle performance during a transient event, i.e. simulations are necessary. It is also found that, except for the shaft speed calculation, the introduction of gas constant and specific heat ratio dependence on the compressor performance map will have only a minor influence on the process performance.


2015 ◽  
Author(s):  
Chenglong Tang ◽  
Zhanbo Si ◽  
Shuang Zhang ◽  
Zuohua Huang ◽  
Shiyi Pan ◽  
...  

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