VES - Heat Exchanger Wizard
Create a project
The VES program organizes equipment in projects. An Engineering Contractor will create the project according to the actual projects at hand, but an Operator Owner, for example, will use the project structure according to the process units and will give projects names similar to process units.
The VES application will start with a similar dialog window as in Figure 1. This window is used to edit the projects that are part of the database or to create a new project. For this example we will create a new project.
After clicking the button 'New' with the left mouse button the following project edit dialog will appear.
The fields in the above New project dialog can be completed to identify the project for later reference. The fields such as the project number will be shown on the calculation sheets. The Authority/Code is the selection of the calculation code used. This calculation code can be changed later, if required.
After completion of the dialog fields click 'Ok' to save the data of the project to the database and you will see a Main Window as shown in Figure 3 .
Notice that the project number is indicated at the left top of the window, here in the blue section. The Main Window will show data of the equipment is selected. There is no equipment yet in the project and no equipment selected, therefor no data is shown.
The first five buttons at the top of the window as shown in Figure 3 are for:
- open an existing project
- create a new project
- close current project
- delete current project
- edit current project
The buttons 6 through 9 are for:
- open an existing equipment
- create a new equipment
- delete current equipment
- copy the current equipment
Heat Exchanger Design Module
From this point there are two possibilities:
- Create each part of the heat exchanger manually
- Use the creation module for heat exchangers
We will use the second option to efficiently create all parts of a standard heat exchanger. Later parts can still be added or deleted. The second option also gives the possibility to create a setting plan, with the first option this is not possible.
Use the arrow next to the seventh button to get the drop down menu and select 'heat exchanger' to create a new equipment (heat exchanger) in the project database. Alternatively, select from the menu Item > New > Heat Exchanger.
The following dialog window will be shown:
Enter the equipment number at 'Heat exchanger number'. An example equipment number used here is 'HE-101'.
Enter the revision or issue number of the calculation. Usually the revision starts '0' or 'A'. The revision number will also be shown on the calculation sheets. The revision is an important identifier of the various issues or updates of the calculations. Enter the date of the revision in the next field to indicate the revision date.
Enter the description or name of the equipment at the 'Heat exchanger description' field. An example of the name is 'Boiler'. The name usually references the process function of the equipment in the unit of the plant.
Enter the username or company name in the 'User name' field. The name will be shown in the title block of the calculation sheets and indicates the originator of the calculation.
Choose a type of head for the closure at the ends. This setting of the type of head will be ignored in case of flat covers at the ends.
Select the type of the supports by clicking one of the radio buttons. The type of saddles is depending the orientation (horizontal or vertical) of the equipment. The type exchanger (horizontal or vertical) and supports can not be changed later since it is a vital part of the data structure in the database
The tube side pass configuration is to be selected for one pass exchangers only. This will set the inlet and outlet nozzle at either side (front/back) of the exchanger. The VES application will than take the configuration into account by creating a larger end channel with the outlet nozzle. In the calculation this nozzle and channel will be added to the calculations.
Select the Tema type clicking the relevant pictures or use the dropdown menus below the pictures. The graphic will show the a general representation of the selected types.
Note: The selection of the Tema type and the support type can not be changed afterwards. If this dialog is closed these settings are fixed because they are fundamental to the creation of the equipment and the selection of the details of the equipment. In case the type of the exchanger is changed the equipment has to be deleted and a new type has to be created.
At the top of the window the main information of the equipment is shown. The fields except for the ItemID can be edited if required. The save button will save the changes made. The VES application has now created the equipment based on the selections made in the previous dialog.
The main window shows in the 'Equipment part list', the relevant parts as indicated in Figure 5. At the 'Equipment part list' the applicable calculation code can be selected, Rules for pressure vessels (The Netherlands), ASME (USA), AD Merkblätter (Germany) and EN (Europe).
The relevant calculations are shown if a part is double clicked or the plus (+) mark next to the part is clicked. The calculations are still empty because the details of the equipment need to be completed first.
From this point there are two possibilities:
- complete all information per individual part
- use the design module for heat exchangers in the VES application
We will start with the design module and use the detail input possibility later for the modifications. The design module is the most efficient method when for example the design temperature and design pressure will be set for a new equipment. The design pressure and temperature is applicable for a number of parts and will be entered for all parts at the same time.
The design module will facilitate the data input for the exchanger. Input data necessary for the different parts of the heat exchanger will be completed in the database by the design module.
After double clicking the 'Heat exchanger design module' in the 'Equipment part list', the design module screen will be opened. For the full data sheet content refer to the appendices.
Enter design data
The following data can be entered of which most is necessary for the calculation unless indicated otherwise:
- Nominal O.D. and the length of the shell, both of these figures are optional and are for indication of the equipment size only
- Connection is an indication of the location of the exchanger. It can be used to indicate a installation in series or parallel. This will provide the designer of the plant information whether exchangers can be stacked.
- The Tema class entrance can be R,C or B as per the Tema code. The selected option is use in the Tema to set the minimum allowed wall thicknesses that can be used in the heat exchanger design. The design option for Tema can be de-activated by selecting in the menu edit > options. At the tab 'General' unselect the 'Check Tema – Minimum' check box. The dialog 'Options' will be explained in the next sections.
- Select the allowable stress option as per code, 0 = ASME, 1 = RtoD, 2 = ADM
- Complete the data for the exchanger, design pressure, test pressure, vacuum pressure, design temperature, insulation thickness, number of passes, etc.
- The test pressure is not used in the calculations and is for completing the datasheet only
- The insulation thickness is used in the application to determine the stand-out required for the nozzles
- Use '1' for the joint efficiency to start the calculation. This value can be altered when the none destructive testing (NDT) details are determined. With the use of '1' the total strength of the material is taken into account in the calculations.
- The material code instructs, depending the Tema code, the program to use the specific 'Minimum Shell Thickness' Table in the Tema code
The buttons 'Nozzle list', 'Material list' and 'Options' in this section are to edit the nozzles, materials and design details. These buttons will be discussed later in this document.
Design data cylinders:
- The inside diameters can be entered by hand. Alternatively the user can use the buttons next to the input fields to select pipe size and schedules when the shells are made of pipe
- The wall thicknesses are optional. The minimum wall thickness is calculated by the program and/or are determined by the Tema code. Otherwise the optional values are used for the calculations
- The nozzle pads can be allowed Yes/No. If nozzle pads are not allowed the program will increase during the design the shell thickness for the minimum required strength. In hydrogen service nozzle pads (reinforcements) are usually not allowed.
- The nozzle pad default width and default thickness are optional and otherwise calculated by the program
Design data girth flanges:
The girth flanges are the flanges at channel and shell side, they are so-called body flanges. Select the type of flange: Straight (S) or Tapered (T). The Straight type is usually preferred since they are cheaper to manufacture.
- The Tema gives a standard gasket width of 3/8” (10 mm) up to a nominal outside diameter of 23” and ½ “ (13 mm) above 23” outside diameter of the shell
- The gasket thickness is not determined by the program. It is usually depending on the vendor used for the gasket, in this case we use 4 mm
- The button next to the 'Gasket Number' will open a new window for the selection of the gasket type. In this window, which will be discussed later, the selection will set the gasket number (for reference in the database only), the facing sketch and the material properties. The thickness, number and facing sketch can also be set manually. For the facing sketch refer to table 2-5.2 of ASME VIII Div 1. 'Effective gasket width”. ( In this table the applicable column needs to be selected depending the type of gasket. It will define the specific width factor toe determine the 'Effective gasket width'.)
- The seating pressure 'y' is determined via the gasket type settings but can be overwritten.
- The gasket factor 'm' is determined via the gasket type settings but can be overwritten.
- The partition factor is depending the number of passes, for example for a two pass there is a 30% more gasket area which needs therefore 130% of bolt tensioning to get to the required seating pressure on the gasket.
Design data tube sheet and bundle:
- The tubesheet thickness is optional, it can be set by the user or will be calculated
- The total allowance is the maximum of the (partition) groove depth and the corrosion allowance at the channel side, plus the corrosion allowance at the shell side as shown in Figure 27. Tubesheet thickness and the allowance determines the thickness of the tubesheet for the calculations.
- The total tube length is including the extended parts. If the tubes are not up to the end of the tubesheet this factor can also be negative. The tubesheet extension is set by selecting in the menu edit > options and tab tubesheet which will open a new window. This window will be discussed later in detail.
- The number of tube holes are the actual holes in the tubesheet. There are two (2) holes per tube in a U-tube type exchanger.
- The outside diameter of the tubes is the nominal dimension for the diameter of the tubes.
- The thickness of the tube wall is usually based on the tables of the Birmingham Wire Gage (BWG), refer to section 9 table D-7M of the Tema Standard.
- The tube hole pitch is the distance between the centerlines of the tubes
- The pitch arrangement is the layout arrangement of the tubes. The layout can be triangular (three tubes on the corners of a triangle) or square (four tubes on the corners of a square).
- The perimeter bundle is the length of the line through the centerlines of the outside tubes. This factor is used to calculate the shear stress between the tubes and the tubesheet, refer to Tema section 5 paragraph RCB 7.133. The factor C will be used to calculate the equivalent diameter DL. The DL is used to calculate the effective (minimum required) tubesheet thickness for shear.
- Enclosed area A is determined by the perimeter C and is calculated by the software
- Largest bend radius is only applicable for U-tubes. The bend radius is used to set the distance and overall dimensions at the end of the bundle.
- Smallest bend radius (only for U- tube) is the minimum allowable radius. An excepted value for the smallest bend radius is 1.0 * diameter of the tube, for spacing requirements at the end head of the heat exchanger.
- The mechanical datasheet usually gives the number of baffle spacings. This value is important for the calculation for the buckling length of the tubes. This is not applicable for the U-tube heat exchangers.
- The central baffle spacing is the distance between the central baffles as indicated in Figure 10
- The baffle spacing tubesheet is the the distance between the stationary tubesheet and the first baffle
- The spacing between the last baffle and the support plate is only applicable for the U-tube heat exchangers. This value will be calculated by the software and is shown on the overall settingplan.
- The thickness of the baffles is required for the calculation of the weights only.
Buttons on the data sheet
The heat exchanger design module has three buttons. The first button is to edit the nozzles that are part of the exchangers. The heat exchanger design module creates a fixed amount of nozzles, in/out for the channel side and in/out for the shell side. When the button 'Nozzle List' is clicked the above window will be opened. Some nozzle data can be updated such as the type, rating, NomOD and the schedule. Other data can not be edited in the VES06A version. (This might change in the future versions)
Note: The nozzles indicated in the above nozzle list from the heat exchanger design module are an integral part of the heat exchanger design and will also be shown on the settingplan. Additional nozzles added to the heat exchanger will be used in the calculations but are not shown on the settingplan and are not part of the nozzle list in the design module.
The nozzle list can also be opened from the menu Edit > Nozzle List of the heat exchanger design module. When opening for the first time the created nozzles are indicated but empty with data.
- The field 'mark' is used to indicated the nozzle on the drawing, this field can not be edited
- 'Service' can be used to indicate the process service or medium
- A button will be shown if the field in column 'Type' is clicked. Click this button to select the type of nozzle from the standard database as shown in Figure 11. With the selection of the nozzle the rating, NomOD and the detail data is set.
Select nozzle rating and schedule
- The 'Facing' is standard set to Raised Face (RF) and can not be edited at this point. The details of the gasket and facing can be changed later in the detail calculations of the nozzles
- In the nozzle list, the 'Rating', 'NomOD' and 'OD' are set by selecting the flange. The values can be edited if required
- 'Schedule' is used for the dimension of the pipe between the flange and the shell. A button is shown when selecting this field. Clicking this button will open the pipe schedule dialog. In this dialog the pipe nominal outside diameter and the schedule can be selected.
- The 'Wall' and 'Tolerance' in the nozzle list are set by selecting the pipe for the nozzle. The values can be edited if required.
- The nozzle list contains the fields 'WRing' and 'TRing' for the optional reinforcement ring. WRing is the width of the ring and TRing is the thickness of the ring. The VES program uses the width of the ring to determine the allowable distance to the nearest weld during design cycle of the equipment.
- The 'StdOut' (stand-out), 'Orientation' and 'Neck orientation' are set by the program but can be set manually.
The nozzle list has now been set with the relevant information of the nozzles. The window with the nozzle list can now be closed. The next step is to complete the material list. Click the button 'Material list' to open the material selection dialog window.
The column with the 'Part description and Location' is completed by the heat exchanger design module. The columns Material, Td (design temperature), S(Td) (allowable stress by design temperature), S(20ºC) (allowable stress by 20ºC) and G (specific weight) are empty. Note: the Td needs to be set otherwise the following fields S(Td) and S(20ºC) can not be determined by the software.
The materials of construction dialog has another tab at the top for the extra material properties.
Click this tab to the modulus of elasticity for custom materials. Normally these values are present in the database for the standard database materials. The elasticity figures are used for the calculation of a fixed tubesheet of the heat exchanger.
After the materials have been set the dialog can be closed and the selected data is stored in the database. Now the main window will be again active of heat exchanger wizard data sheet. At the right top of the sheet click the button options.
A dialog as shown in Figure 15 is opened when selecting the options button on the heat exchanger data sheet. The dialog has various tabs which allow the user to set the relevant data for the heat exchanger.
The dialog is normally filled with default values. These values have been developed based on many years of experience in the industry and can be used for a first estimate of the heat exchanger. For example the confining height and depth values are based on general fabrication practices.
- The 'TEMA minimum' is checked when the minimum values of the TEMA need to be observed for wall thicknesses of shells and heads. This can be unchecked if for instance the UHX of the ASME VIII div1 is used as calculation basis. If this option is on: The shell barrel and channel thickness will be designed starting with a minimum thickness according TEMA section 5 RCB-3, and the diameter and design pressure are checked against there maximum values from TEMA
- The software uses some small extra design margins for flanges and tubesheets. If this options is selected the the program will use the exact calculated figures. All design sizes are not rounded to the nearest integer values. This options is for special cases for which it is important to known the exact required wall, flange and tube sheet thickness
The general flange parameters are illustrated in Figure 16 and Figure 17
- The confining height of a flange is indicated by number 1
- The confining depth of a flange is indicated by number 2
The general tubesheet parameters are illustrated below in Figure 17.
- The spacing confining diameter flange and tubesheet is the difference between the arrows indicated by number 6 and 7
- The confining height tubesheet large diameter is indicated by number 3
- The confining height tubesheet small diameter is indicated by number 1
- The minimum confining width near bolt hole is illustrated in Figure 16 with number 3
- The minimum confining width near bolt hole for a dished cover or floating head flange is indicated by number 1
- The groove depth is illustrated with number 4 in Figure 19
- The miscellaneous weights are the user defined weight for auxiliaries such as name plate, name plate bracket, earthing connections, lifting lugs and others
- The head type can be set and will be used for both ends
The heat exchanger flange options can be edited when selecting the tab 'Flange'. Below in Figure 20 the various fields are shown that can be set by the user.
- The minimum hub height is illustrated in Figure 16 (6)
- The hub height coefficient is used to calculate he hub height depending on the connected cylinder thickness (7).
- The default hub slope is 1:3
- The hub flange transition radius is the radius between the flange and the hub section.
The above four items are usually depend the tools of the fabricator and the required distance to the next weld on the equipment.
The gasket settings are show below in Figure 21 and Figure 22.
- The design for minimum gasket reaction diameter corresponds with the Gmin location of the gasket, Use the design for MINIMUM gasket reaction diameter option for heat exchangers with high design pressures. The flange design will minimize the flange pressure area. Use this option to optimize the flange thickness for high pressure cases
- The design for maximum gasket reaction diameter is indicated with option Gmax.
- The check minimum gasket width can be selected to make sure that the gasket width will be checked against the minimum required width for the applied packing pressure
- The heat exchanger design will start flange design with the minimum bolt size from the flange option window (default minimum bolt size is ¾”). Use this option if the design returns with a large number of bolts. A larger minimum bolt size will reduce the number of required bolts
- The bolt type is depending on the bolt tensioning tools used to close the flange connection. Click the 'Bolt sizes' button to view the bolt dimensions used to construct a flange
- The floating head can contain a split backing ring. The correction factor is to increase the stress loads due to higher moments. The moment correction factor for a split backing ring is depending on the number of splits (default Cfsplit = 2)
The tab tubesheet in the design options window provides the setting for the tubesheet detail dimensions and the U-tube distances to the rear head of the heat exchanger. The following picture illustrates the front or rear end tube extension.
The extensions are usually required for tube expansion in the tube sheet or welding purposes. The tube extension can be also zero in case of a vertical heat exchanger where the fluid has to flow from the top tubesheet in to the tubes.
The tubes in a U-tube configuration have clearances at the end head or bonnet which can be set by the user. These values are for drawing and positioning of the components only and have no influence on the calculations.
- The clearance of U-bends to bonnet is illustrated with number 1 in Figure 29
- The clearance between the support plate to the U-bend is indicated with number 2
- The extra tube length per U-bend is to ensure that enough clearance remains between the various U-tubes with different radii. A common distance is 6 mm increase per larger U-tube bend radius.
The tube sheet extensions reduction is indicated with number 5 in Figure 17
The Outer Tube Limit (OTL) to confining diameter in a floating tubesheet is indicated with difference between number 1 and 2. Figure 28
Custom Body Flanges
The detail dimensions of the (body) flanges can be edited in the dialog window with tab 'Flange Thickness' as shown in Figure 30.
The thickness including the confining depth can be set per flange. For the flange numbering refer to Figure 31.
Not all numbers are present for all types of exchangers, for example flange 3 and 4 are not present in case of fixed tubesheets. In case of a BEM type flange number 1 will not exist.
- The flange thicknesses are optional because if left empty by the user the software will calculate the required thickness, including the thickness required for corrosion.
- If empty the number of bolts will be determined by the software. In case of an existing exchanger or user preference the number of bolts can be set as basis for the calculations.
- The entered flange thicknesses and number of bolts can be locked. When a new heat exchanger design cycle is performed the software will not change these values.
In case of an existing exchanger the thickness of the flange is usually set set as a basis for the calculations and will be locked. The values will not be changed by a design cycle.
The design cycle is executed by selecting in the menu:
View > Design & view construction sizes
The options from the menu View > Check & view construction sizes will only show the calculation values of the last design cycle and the optional values are not changed, even if they were not locked. Note: the floating head is not part of the flange numbering above.
The floating head and backing ring details are only applicable for exchangers with a floating head. The other type of exchangers will ignore the entered values in this section.
- The number of bolts can be entered by the user for the floating head. If left empty the software will determine the number of bolts when a design cycle is executed.
The number of bolts are determined by the software using good engineering practice. The basis of the design practice or procedure is as follows:
The design cycle uses a fixed ratio for the floating head flange which is A : B = 1 : 2.5. Based on engineering experience this provides a good starting point for the design of the floating head flange. With this ratio the polar moment of inertia is almost equal for the same area.
The software will first start with a minimum bolt size form the TEMA code and will determine an initial value for the cross section area. From that point an iteration process will start and will increase the area dimensions in both directions such that the are ratio will remain around 1: 2.5. which is the most effective design considering the material weight.
The torque lever arm 'C' is determined during the iteration process. The area required for welding is taken in to account.
- The total height of the backing ring is indicated with D
- The thickness and confining of the floating head flange is indicated with B+E
- The thicknesses and number of bolts can be locked. This will prevent that the values will be changed during the design cycle of the heat exchanger.
The settings of the options can be printed by clicking the print button at the bottom of the options dialog window. A spreadsheet like overview will be shown which can be exported to an MS Excel spreadsheet or send to printer as shown in Figure 33.
The design options overview is a reference document that can be used to quickly check the settings which were used during the design cycle. The various values are used in the calculations and are indicated again in the calculation were relevant.
- The software will maintain, during the design cycle, a clearance between the weld of the nozzle and the next weld on the shell or head. The clearance is set in the field 'Clearance weld to reinforcement ring'. In case of a reinforcement pad this clearance will be between the edge of the reinforcement pad and the next weld on the shell, refer to 1 and 2 on Figure 35 and Figure 36.
- In certain circumstances for example in existing exchangers the reinforcement area in the channel is not wide enough for the required area. The 'Allow reinforcement area channel in skirt' check mark can be set to allow the calculation to use the additional width of the skirt of the head for the reinforcement area calculation.
- The nozzle positions are optional. During the design cycle the VES program will determine the optimal position for the nozzles. The user can set nozzle positions to comply with the requirement from for example piping engineering. The nozzle positions can be locked to fix the user set positions during the design cycle.
- The nozzle orientations are also optional. The user can set the orientation as required and can also lock the position for the design cycle.
The nozzle positions can be changed in detail when reviewing the detail calculations. For example if the ASME UG-37 (Nozzle reinforcement) calculation is opened the nozzle positions can be changed by selecting in the menu Options > Position and Orientation or to click the button on the calculation sheet at line with 'Nozzle location angle to x-axis ?'.
The nozzle orientation can be manipulated by dragging the nozzle with the pressed the left mouse button on the image.
The VES program will automatically determine the optimum position of the saddles during the design cycle of the heat exchanger. The program will assume that both inlet and outlet nozzles are at the bottom when positioning the saddles. The saddle distance will be set at a minimum distance inside both the nozzles taking into account the required access for bolt fixation tools.
The position of the saddles and the standout of the saddles can be set by the user to adjust the position. The positions can be locked to prevent changes by the program when running a new design cycle.
Refer to 1 and 2 in Figure 39 for the nozzle to saddle position.
- Gives the 'Distance Center Line tubeside nozzles to nearest saddle'
- Is the 'Distance between saddles'.
- The Saddle standout is measured from the centerline of the exchanger
Alternative Shell Design
The heat exchanger design input sheet shows two small buttons at line of 'inside diameter' in the section of 'Design data cylinders'. The shell and channels can be made of plate or using a schedule pipe. The diameter can be set by the user in case of a plate. By clicking the buttons a window as in Figure 40 below is shown.
The user can now select a standard pipe schedule for the channels and shell.
- Select at the top of the window the standard from which the schedule will be selected
- Select with a left mouse click the require nominal outside diameter of the pipe to be used
- At the right of the window select the applicable schedule
- One from two options can be selected for the tolerance tube or plate tolerance. The tube tolerance will use standard 12.5% of the nominal thickness. The plate tolerance is 0.5mm. The actual tolerance and NomOD are shown in the two (non-editable) fields for reference.
The heat exchanger design input sheet shows one small button at line of 'Gasket number' in the section of 'Design data girth flanges'. Pressing this button will show the gasket selection window (Figure 41).
- Click in the list to select one of the gasket types
- For the facing sketch refer to ASME VIII div1 appendix2 table 2-5.2, commonly used is 1a
- The column I or II is depending the used gasket, refer to table 2-5.1
- The values for gasket thickness, gasket width and facing width are set by the software after selecting the gasket data but can be edited by the user as required
Design & View Construction Sizes
The mechanical datasheet for the heat exchanger has been completed in the previous sections. All necessary data for the design of the heat exchanger is now available in the application.
The Design & View Construction Sizes is the instruction for the VES application to run a new design cycle based on the data in the datasheet entered by the user. The software will perform the calculations and will design the dimensions such as bolt circles, flange sizes and nozzle reinforcement.
The design instruction is used when a first calculation or design is done for a new heat exchanger. The design cycle uses the knowledge of an experienced engineer to make decisions about dimensions and thicknesses. It is also interesting in some cases to see what the VES software would have made of an existing design.
In the menu click View > Design & View Construction Sizes.
A new window will be opened with the design report showing the results of the calculations. The window has various tabs at the bottom. One of the tabs is shown in Figure 42 showing the dimensional sketch of the exchanger.
The first tab shows the log of the calculations. This log is a report of all the calculation warnings, errors, input settings and inconsistencies. This first log is the first indication of the soundness of the calculation. The user is advised to update the input of the data first to remove all errors and warnings before detail editing is done to the heat exchanger design.
The next tabs contain the actual input and result report, with:
- cover sheet of the report
- mechanical data sheet, which is an echo of all user input
- dimension sheets, showing the dimensions as designed by the software
- nozzle list, listing the data of all the heat exchanger nozzles
- material list, showing the selected material per heat exchanger item
- sketch, a sketch of the heat exchanger type with the size values
It is possible to review the last design cycle report without running the full design. The previous report generated by the last design cycle is selected in the heat exchanger design module by clicking in the menu: Check & View Construction Sizes
The weight table shows the weights of the various components, the bundle and the empty exchanger. Click in the menu View > Weight
The log data with warnings and errors is also available from the menu, click View > Assessment.
Material and Nozzle Data
The first draft design is done with the heat exchanger design module as described in the previous sections. If the heat exchanger design module window is still open close the window by select from the menu File > close. The main window will now be visible of VES.
In the main window, just below the the Heat Exchanger Design Module, the link to the Material List link is indicated. If clicked a window similar to Figure 44 below is shown.
The material list gives a similar overview of the materials used as the material list in the heat exchanger design module. The materials can be edited in this window by double clicking the relevant material field. A new material selection window will be opened to facilitate the material selection.
The material property columns are as follows:
- Td[°C] is the user set design temperature for the exchanger item
- Rm[N/mm2] is the tensile strength at 20 °C
- Re[N/mm2] is the yield strength at design temperature
- Re 20 °C[N/mm2] is the yield strength at 20 °C
- Rmg[N/mm2] is the average creep tensile stress
- E[N/mm2] is the modulus of elasticity at design temperature
- E 20 °C[N/mm2] is the modulus of elasticity at 20 °C
- Alpha [1/°C] is the linear expansion coefficient
- Sall[N/mm2] is the allowable stress at design temperature
- Sall. Atm.[N/mm2] is the allowable stress at atmospheric conditions
- Specific gravity[Kg/dm^3] is the specific gravity
Below the Material List link is the link to the Nozzle List. Double click this link to open the nozzle list window as shown in Figure 45
To change a selected nozzle click the relevant Flange Rating or Flange Type field. A gray box with a down arrow can be clicked to open the Nozzle Selection dialog window. The user can select a standard flange and size from the nozzle selection dialog.
Standard a raised face (RF) is entered at the flange facing field.
To edit the nozzle neck or connecting pipe click the Neck Nominal OD, Neck OD or the Neck Schedule field. A gray box with a down arrow can be clicked to open the Schedule selection dialog window. The use can also select here the standard pipe schedule and size from the database.
The following fields can be edited also manually instead of selecting from the database:
- neck thickness, in case there is no pipe schedule available
- neck joint efficiency
- neck tolerance
The reinforcement width and thickness can be set by the user. This value is or set by the heat exchanger design wizard or set manually in case of an existing exchanger.
The standout of the nozzle is defined from the centerline of the heat exchanger shell and channels. The Remarks column is for user remarks as reminder when opening this window.
Detail Design of Heat Exchanger
The detail design and update of the exchanger calculations starts after the using the design wizard and finalizing the setting for materials and nozzles.
The main window of VES will show something like below.
The calculations relevant to channel 1 will be opened with a double click on the text 'Channel 1' or a single click on the plus '+' sign. In above picture the relevant ASME calculation shown are UG-27, UG-28, etc.
Double click the calculation to open the calculation sheet window. The user can edit the input fields and click in the menu 'Calculate' to execute a recalculation based on the edited values.
The calculation sheet for UG-37 (openings in a curved wall) is shown below in Figure 47.
This window has an additional editing possibility to position the nozzle. In the menu click Options > Position. A window similar to the one shown in Figure 47 will be opened.
The user can change the nozzle position by dragging with the mouse the nozzle to the required position.
This concludes the heat exchanger design wizard description. For detail design of heat exchangers and pressure vessels or other VES tools, please refer to the relevant documentation.