ORIGINAL_ARTICLE
Prediction of Temperature Profile of a Buried Gas Pipeline Through Utilization of Corresponding States Principle
A new analytical equation for prediction of temperature profile of a buried gas pipeline is developed. Utility of this equation is illustrated by its application to corresponding states principle. The resulting equation is tested through prediction of the actual Schorre data. It is shown that the new equation can predict temperature profile more accurately than the others without using any chart of tables. This equation can also be used for prediction of gas mixture temperature profile flowing in a buried pipeline.
https://www.ije.ir/article_70993_c9196791c790a2c8b52d64478bab9865.pdf
1989-05-01
1
4
K.
Adham
hasnomail@ije.ir
1
, Ministry of Culture and Higher Education
AUTHOR
M.
Edalat
medalat@ut.ac.ir
2
Chemical & Petroleum Engineering, University of Tehran
AUTHOR
ORIGINAL_ARTICLE
Molecular Dynamics Simulation of Potassium Chloride Melting(.I. Microcrystal Simulation and Sample Size Effect)
The effect of sample size on the melting parameter of simulated potassium chloride microcrystal is investigated by molecular dynamics simulation. The size of microcrystal is varied from 8 to 4096 ions. The increase in melting temperature with sample size was found to be in good agreement with the theory.
https://www.ije.ir/article_70994_4b329b82ebb37fadd5dfeacebd9bf7f0.pdf
1989-05-01
5
13
S. Mohammad
Amini
hasnomail@ije.ir
1
Physics, Isfahan University of Technology
AUTHOR
ORIGINAL_ARTICLE
Molecular Dynamics Simulation of Potassium Chloride Melting (II. Constant Volume and Constant Pressure Simulation of Filled System)
We have used a simple ionic potential to simulate the melting of KCI pseudo-infinite crystal. Two MD simulations, one with constant Volume and the other with constant pressure condition are performed. These results are compared with the previous micro-sample simulation results. In the constant volume simulation the melting temperature increase substantially with increasing pressure. A method for constant pressure MD simulation of melting is discussed.
https://www.ije.ir/article_70995_c1e6c2a9ae29a8b12828e409df41ac48.pdf
1989-05-01
15
24
S. Mohammad
Amini
hasnomail@ije.ir
1
Physics, Isfahan University of Technology
AUTHOR
ORIGINAL_ARTICLE
New Methods for Harmonic Reduction in T. C. R. by Sequence Control of Transformer Taps
Thyristor controlled static compensators consist of two basic schemes, TCR and TSC. Owing to the discontinuous current in TCR, current harmonics are generated in the supply system. This paper introduces two methods for the reduction of these harmonics. On the basis of the coordination or uncoordination of turn ratios with harmonic reduction levels, each method is described in two alternative schemes. By using either one of these methods, the magnitude of harmonics may be reduced and their undesirable effects in power systems minimized.
https://www.ije.ir/article_70996_c1e6c2a9ae29a8b12828e409df41ac48.pdf
1989-05-01
25
34
G.R
Zaker
hasnomail@ije.ir
1
Electerical Engineering, University of Tabriz
AUTHOR
S. H.
Hosseini
hosseini@tabriz.ac.ir
2
Electerical Engineering, University of Tabriz
AUTHOR
ORIGINAL_ARTICLE
A Numerical Design Technique for a Relay - Type Feedback Control System
An efficient numerical method for the design and synthesis of compensator for a relay type control system is developed and discussed. Previous works based on the interactive graphic method are reviewed and it is shown that the combination of the trequency and time domain numerical techniques provide a powerful tool in design of a wide class of relay control systems. An example is presented to demonstrate the efficiency of the procedure.
https://www.ije.ir/article_70997_283b2a2fdfa362b84f803a974470921a.pdf
1989-05-01
35
44
S.D.
Katebi
skatebi@postmaster.co.uk
1
Computer Engineering, Shiraz University
AUTHOR
ORIGINAL_ARTICLE
Enhancement of Natural Convection Heat Transfer in Annular Enclosures
Natural convection heat transfer was investigated experimentally in a concentric-cylinders annulus. To enhance the rate of heat transfer, pin fins were installed on the surface of the inner cylinder. Two fin arrangements were employed, namely, staggered and in-line arrangements. The length of the fins varied from 2 to 8 cm and the Rayleigh number Ra changed in the range from 5 x 105 to 5 x 106 The heat transfer medium was air at atmospheric pressure. So, the results reported here are for the Prandtl number Pr 0.7. It was found that, while the presence of fins usually decreases the heat transfer coefficient, the resulting increased surface area due to fins is so significant that the fins of both arrangements increase the rate of heat transfer. with the staggered one being more efficient. The normalized rate of heat transfer Q i / Q 1 was found to be independent of Rayleigh number, and for each fin arrangement, correlations were obtained to express Q i / Q 1 as a function of fins length. In the range of parameters considered in this work, the overall rate of heat transfer increased as much as 300%, corresponding to the longest fin of the staggered arrangement.
https://www.ije.ir/article_70998_1f98534d692750718991759626d9c3da.pdf
1989-05-01
45
54
M.
Shahsavan
hasnomail@ije.ir
1
Mechanical Engineering, Isfahan University of Technology
AUTHOR
Majid
Molki
mmolki@siue.edu
2
Mechanical Engineering, Southern Illinois University
AUTHOR
ORIGINAL_ARTICLE
Computer Simulation of Hydrodynamic Behavior of Aggregative Fluidized Beds
Hydrodynamic behavior of aggregative fluidized beds has been studied and a model proposed for the prediction of different characteristics of fluidized beds. According to this model, a computer program is prepared and the hydrodynamic behavior of some industrial units has been simulated.
https://www.ije.ir/article_70999_eb8338b8fb5e2761ae5dc688186dfd84.pdf
1989-05-01
55
64
M.T.
Babayan
hasnomail@ije.ir
1
Chemical & Petroleum Engineering, Shiraz University
AUTHOR
D.
Mowla
dmowla@shirazu.ac.ir
2
Chemical & Petroleum Engineering, Shiraz University
AUTHOR
ORIGINAL_ARTICLE
Investigation of Dual Fuel Diesel Engine With Particular Reference to Engine Cycle Model
In order to use gaseous fuels in Diesel Engines, Dual-Fuel Diesel Engine (D. F. D. E) the pilot injection approach is chosen. To predict its performance, an engine cycle model, based on limited-pressure Diesel cycle, is constructed. The model predicts D. F. D. E performance with LPG, and CNG gases. Comparing with pure Diesel engine, by increasing gas proportion in dual-fuel, indicated power and hence indicated mean effective pressure are increased. Effect on thermal efficiency is not so appreciable, but indicated specific fuel consumption is quits considerable, and hence fuel economy of D. F. D. E is superior.
https://www.ije.ir/article_71000_912a9547c5a4fc3d489cb20c7c6c2bb8.pdf
1989-05-01
65
70
V.
Pirouzpanah
pirouz@tabrizu.ac.ir
1
Mechanical Engineering, University of Tabriz
AUTHOR
Y.
Asadi
yousef_asadi@yahoo.co.uk
2
Mechanical Engineering, University of Tabriz
AUTHOR
ORIGINAL_ARTICLE
Biomechanical Responses to Experimental open Spinal Cord Injury
https://www.ije.ir/article_71001_f0ef3f58ce19efd6951a5d5430315d44.pdf
1989-05-01
71
77
M.R.
Hashemi
hashemi@comnete.com
1
Engineering, Sharif University of Technology
AUTHOR