Effect of Mill undertollerance on Shell thickness calculation

Technical,

During design of pressure vessel, I came across this issue number of time. Unfortunately, ASME VIII Div.1 doesn’t give a clear picture, whether to add the undertollerance in the min. required thickness as calculated by ASME VIII Div.1 ASME VIII Div. 2, give a clear cut understanding on this issue, can clears all ambiguity. (Clause…

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Heat exchanger : Good Ref. Site

Technical

To have more ‘Visual’ Clarity, visit following site! http://www.hcheattransfer.com/shell_and_tube.html Take Care!

Tube Holes in Tubesheet : Point to ne noted while designing heat exchanger

1 CommentTechnical

Tube hole finish affects the mechanical strength and leak tightness of an expanded tube-to-tubesheet joint. In general: (1) A rough tube hole provides more mechanical strength than a smooth tube hole. This is influenced by a complex relationship of modulus of elasticity, yield strength and hardness of the materials being used. (2) A smooth tube…

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Design of heat exchanger step :5 : Parameter Calculations

11 CommentsTechnical

In the process of evaluation of U, we need to calculate various parameters. Below paragraph mentions few of them. 1. Reynolds number (Re) Reynolds number, which relates inertial forces to viscous forces and thereby characterizes the type of flow regime2. Prandtl number (Pr), which relates the thermal properties of the fluid to the conductivity of…

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Differences Between The Eighth And Ninth Edition Of The TEMA

Technical,

Ok, TEMA Ninth edition is here. Other Than complete change in Page Indexing (Page number), Following are note worthy changes from eigth edition : Followings are Prominent Changes and Listed at TEMA website 1. New rules for flexible shell elements (expansion joints), which are based on a Finite Element Analysis (FEA) approach. 2. Tables for…

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Design of heat exchanger step :4 : Thermal Design

8 CommentsTechnical

Next step, do a detailing. To Calculate LMTD, we need to understand the flow and type of process (Isothermal or not) Generally we have complication, when either of fluid is showing isothermal characteristics. see the following variation. Two fluids are separated by a heat transfer surface (wall), these fluids ideally do not mix, and there…

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TEMA Learning -Heat Exchanger nomenclature & Designation:

2 CommentsTechnical

Heat Exchanger nomenclature & Designation:The name is splited in three portions e.g 23-192-BEM 1st Position : 23 : Defines, ID of Vessel2nd Position : 192 : Defines, Tube length3rd Position : BEM : it further splited in three parts as per fing N-1.2e.g B-E-M, the 1st section, defines the Type of Front head (B for…

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Design of heat exchanger step :3 : Estimate

1 CommentTechnical

The 3rd Step in Heat exchanger design a preliminary estimate of the size of the exchanger is made,using a heat-transfer coefficient appropriate to the fluids, the process,and the equipment. Generally we can get reference from various resources listed below, either expected heat flux (W/m2) or range of heat transfer co-efficient. based on this information, we can…

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Thermosiphon Reboiler Design

1 CommentTechnical

During Resent days, I was trying to design thermosiphon reboiler! After long days of calculation, rewriting calculations on pages! on excel! finally I come to some ‘lesson learn’ which I’ll  be sharing now. But before that, following are two good references to design a thermosiphone reboiler1. Applied Process Design Volume-3 by Ludwig2. Process Heat Transfer –…

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Design of heat exchanger step :2 : which type?

5 CommentsTechnical

The next step is to decide which type of exchanger to be used?The industrial heat exchanger are varies depending upon 1. Transfer process.2. Number of fluids3. Compactness.4. Constriction.5. Flow arrangement.6. Type of heat transfer.See attached figure for more details.

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