International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 10 Issue: 05 | May 2023
p-ISSN: 2395-0072
www.irjet.net
Design, Analysis and Comparative Study of Exhaust Manifold for a Multi-Cylinder Four Stroke SI Engine using CFD Vivek Chaudhary1, Dr G. Amba Prasad Rao2 1Post Graduate Student, Dept. of Mechanical Engineering, NIT Warangal
2Professor, Dept. of Mechanical Engineering, NIT Warangal, Telangana, India
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Abstract - Gas exchange phenomena of an IC Engine take
so many components, it is impossible to replicate the actual scenario in a model. The output gases from more than two cylinders are collected into a single pipe in an exhaust manifold of any multicylinder engine. The outlet of the multicylinder heads is connected to the inlet of the multicylinder exhaust manifold. In multicylinder engines, the exhaust manifold is attached to the engine and is the principal portion where the stream from multiple cylinders is to be collected into a single pipe. The accumulated hot exhaust gases exit through the single exhaust manifold outlet from the cylinder header. For the engine to work optimally, the backpressure of the exhaust manifold at the output should be reduced. For domestic automobiles, the higher the backpressure, the poorer the performance or economy. Higher backpressure is required for race cars to reach higher speeds in less time. To achieve optimal mechanical and thermal efficiency, the exhaust gases should have a high velocity at the exhaust manifold's exit.
place through intake and exhaust manifolds. The engine’s performance is influenced by the gas exchange process. The engine's performance improves when the exhaust manifold is in good condition. In the present work, an attempt is made to the modify exhaust manifold by upgrading its design for improved performance for a chosen multi-cylinder engine configuration. The primary objective of the present work is to enhance the design to reduce backpressure in the exhaust manifold for enhanced engine performance. Computational fluid dynamics (CFD) is a popular and current operating software that is widely used. CFD is largely used in the automobile industry to lower the cost of designing and analyzing various models in the fluid flow area. The flow through the exhaust manifold is performed using commercially available software. Efforts are made through CFD software to analyze various shapes of exhaust manifolds. Five distinct models were built and thoroughly analyzed using velocity and pressure contours to get the optimum shape for minimal backpressure and high exhaust velocity. The velocity contour and pressure contour are used to compare six distinct models, and the best potential model for low backpressure and high exhaust velocity is given. Among the six models designed, model 6 yielded satisfactory performance.
Table -1: Engine Specifications Engine
4 Stroke 4 Cylinder SI Engine
Make
Maruti-Suzuki Wagon-R
Key Words: Multi-Cylinder Engine, Exhaust Manifold, Back Pressure, Exhaust Velocity, Exhaust Temperature.
Calorific Value of Fuel (Gasoline)
45208 KJ/KG-K
1.INTRODUCTION
Specific Gravity of Fuel
0.7
Bore and Stroke
69.05 mm x 73.40 mm
Swept Volume
1100 cc
Compression Ratio
7.2:1
Dynamometer Constant
2000
Diameter of Orifice
29 mm
Coefficient of Discharge of Orifice
0.65
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One of the most significant components of an IC engine is the exhaust manifold. Exhaust manifold design is a challenging technique because it is dependent on many parameters such as exhaust velocity, backpressure, mechanical efficiency, and so on. The importance of any of these criteria is determined by the designer's requirements. Backpressure, exit exhaust velocity, and power required are some of the exhaust manifold design considerations. The exhaust manifold is constructed of cast iron or stainless steel. It collects gases from several cylinders and routes them to the exhaust manifold. Many studies and research have been conducted in this topic. The study's goal is to gain a thorough understanding of the manifold operation, flow property distribution, and heat transfer details. Due to the inclusion of
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