Heat Exchanger Design - Seminar Topics Computer Science, …换热器的设计-计算机科学研讨会的主题，….ppt

Heat Exchanger Design Anand V P Gurumoorthy Associate Professor Chemical Engineering Division School of Mechanical Building Sciences VIT University Vellore, India Heat Exchanger Classification Recuperative: Cold and hot fluid flow through the unit without mixing with each other. The transfer of heat occurs through the metal wall. Regenerative: Same heating surface is alternately exposed to hot and cold fluid. Heat from hot fluid is stored by packings or solids; this heat is passed over to the cold fluid. Direct contact: Hot and cold fluids are in direct contact and mixing occurs among them; mass transfer and heat transfer occur simultaneously. Heat Exchanger Standards and Codes British Standard BS-3274 TEMA standards are universally used. TEMA standards cover following classes of exchangers: Class R – designates severe requirements of petroleum and other related processing applications Class C – moderate requirements of commercial and general process applications Class B – specifies design and fabrication for chemical process service. Shell and Tube Heat Exchanger Most commonly used type of heat transfer equipment in the chemical and allied industries. Advantages: The configuration gives a large surface area in a small volume. Good mechanical layout: a good shape for pressure operation. Uses well-established fabrication techniques. Can be constructed from a wide range of materials. Easily cleaned. Well established design procedures. Types of Shell and Tube Heat Exchangers Fixed tube design Simplest and cheapest type. Tube bundle cannot be removed for cleaning. No provision for differential expansion of shell and tubes. Use of this type limited to temperature difference upto 800C. Floating head design More versatile than fixed head exchangers. Suitable for higher temperature differentials. Bundles can be removed and cleaned (fouling liquids) Design of Shell and Tube Heat Exchangers Kern method: Does not take into account bypass and leakage streams. Simple to apply