ANNOTATED SAMPLE DATA FOR A  FOUR  CYCLE FRASCA ROTARY ENGINE WITH:
 TYPICAL OPERATING PRESSURES
GENERAL INFORMATION AND INSTALLATION INSTRUCTIONS FOR:
FRASCA ROTARY ENGINE DESIGN PROGRAMS.  Version 98-2e.   Copyr., 1986-2000 by Joseph F. Frasca
!!! THE PROGRAMS WILL NOT FUNCTION OUTSIDE OF THE DIRECTORY (FOLDER) FRASCA. !!!
 Heat transfer program sections are not included.
THE PROGRAM SECTIONS AND A BRIEF EXPLANATION OF THEIR PURPOSE.
RUN PROGRAMS SEQUENTIALLY.
1FRASCA This program is used to indicate the engine's basic physical characteristics.
2FRASCA  This program is used for partition design and acquisition of the cam-partition hydrodynamic interaction data. 
This program need not be run for the other programs to function properly; i.e. its data is not needed. 
3FRASCA  This program is used for the engine's basic compressor and operating environment data and must be run before programs  4FRASCA and 5FRASCA. 
Program 8FRASCA can be used immediately after this program for the graph of  its  data.
4FRASCA This program generates the basic thermodynamic data for the engine. 
Program 8FRASCA can be used immediately after this program to graph the generated data. 
5FRASCA This program generates the engine's performance data. 
Program 8FRASCA can be used immediately after this program to graph the generated data. 
6FRASCA This program  determines the engines axial bearing loads, annular cavity circumferences, and the annular cavity  and its sections centroid radii and their location.
8FRASCA This program can be used after the programs 3FRASCA, 4FRASCA, and 5FRASCA to graph the VVC  temperature and pressure data generated by the respective program sections.
CRFRASCA This program  is used to generate the basic design data for an engine with a circular section annular cavity profile and the engine's VVC volume polynomials.
4-CYCLE ENGINE DATA
PROGRAM SECTION: 1FRASCA.exe
After each data entry press the enter key.

SCREEN 1
   i1) Enter "1" to select FRE design with recessed face surface.
   i2) Indicate with a '4' that the engine is 4 cycle.


 

SCREEN2
In this data  input screen the size of the injection-ignition region of the 4 cycle engine is selected.  The selection runs from an engine with an effectively constant volume injection-ingnition- combustion process, selection 2, to the partially constant volume but generally variable volume injection-combustion process, selection 1.
   i1) Enter 1
   i2) Next enter a few characters for an engine serial number - or just press enter.
   i3) Next enter '1' to indicate that the engine design will have exhaust gas
SCREEN3
In data screen 3 the basic engine configuration and dimensons are selected.
   i1) Major radius: 6"
   i2) Minimum partition radius: 2"
   i3) Number of VVC in the engine: 10
   i4) Minumum partition angular extension into the annular cavity: 8 deg.
   i5) The partitions' angular movement in the cavity: 18 deg.
   [The partition pivots cyclically between 8 and 26 degrees into the cavity during its travers of the annular cavity.]
   i5) The face surface angle: 90 deg.
   i6) The maximum partition length: 6.5"
   i7) The minimum partition thickness in multiples of 1/32": 1
Next the program indicates the maximum compression ratio the particular engine dimensions permit.
In this case: 17.27
   i8) The compression ratio selected is : 9
Using the data input the program geneates a first estimate of the engine displacement, VVC and cavity dimensional data..  The displayed data is generated using partitions with constant thickness set at the minimum partition thickness. 
Other data generated and displayed relates to heat transfer parameters and are not relevant.  The recess torq factor is a volume parameter.
SCREEN 4
A selection of possible partition materials is displayed for selection.
   i1) Silicon Carbide is selected: (10)
THE program indicated the mass and strength of the partition material selected.  The data will be used to determine the partition taper and inertia in a  later program section.
Although fluid bearings are at the partition pivot, a needle or ball radial and thrust bearing combination is used to  determine the partition taper requirements.
   i2) The radial pivot bearing OR is: .25"
   i3) The thrust pivot bearing OR is: .9"
   i4) The thrust pivot bearing effective load radius is: .8"
SCREEN 5
With the atmospheric pressure and  temperature input, this program section displays the incremental generation of the VVC thermodynamic properties (in an isentropic adiabatic process) to the end of the engine compression region. An isentropic process is one where the entropy of the process remains constant.  dS/dT = 0. constant. 
An adiabatic process is one where in no heat is added or removed from a system; i.e. dQ = 0.    n this instance the VVC chamber contents undergoing compression are considered perfectly insulated from all surroundings and the work required for their compression is exactly that work generated if they were allowed to expand.
   i1) Ambient air pressure: 14.7 psi
   i2) Ambient air temperature: 90F degress.
SCREEN 6
An increment by increment estimation of the thermodynamic properties of a  VVV  during its traverse of the engine combustion region is displayed in this section.  The pressure data so generated will be used to determine the necessary partition taper in the next section.  The program also asks for the pressure boost of the fuel methane over the combustion pressure to estimate and display the minimum fuel pump torque loss.
   i1) The pressure boost of methane over the combustion pressure: 50 psi.
SCREEN 7 
This screen displays an increment by increment display of the acquisition of the partition taper and the effecting loads and stresses.  The program  needs input of the type of partition lateral area estimation used, pseudo or close estimate; i.e. l(11) or l(12) respectively.   The program also requires input if a constant thickness partition is desired.  This selection is only suitable in very low pressure engines.
   i1) Type of partition lateral area estimation to be used in the partition taper acquisition.  Enter '1' 
   i2) If a constant thickness partition is desired enter 1: No entr
Finaly, the program generates and displays the actual engine characteristics with tapered partitions.
An additional screen which permits the printout of generated data is ignored.

PROGRAM  SECTION:  2FRASCA.exe
Program section   2FRASCA is used to determine the necessary  partition guide's hydrodynamic bearing characteristics along with the partition's moment of inertia and other critical design parameters.
Where the partition displacement is effected by coaction between a guide spring and guide rotor cam-bearing interaction, the spring parameters are also determined.
Although a second rotor cam and larger lubricant supply are required, engines with  partitions having both a proximal and distal guide each with a hydrodynamic bearing which together coact to effect pivotal displacement should be much less costly to manufacture and much more durable.

SCREEN 8 -
This screeen's purpose is self explained and only appears in the freeware downloaded prior to 02-17-00. 
Press to enter key to move on.
SCREEN 8
The partition guide orientation is selected on this screen.
    i1) Select the proximal guide partition by entering: `A'.
SCREEN 9
The partition's dimensions critical to its pivoting are entered on this screen.
     i1) The partition guide's thickness is entered  as: .12".
     i2) The partition guide's width is entered as : .4".
     i3) The rotor cam minimum radius is entered as: 3"
     i4) The maximum rotor cam grade angle is entered as: 18 degrees.
     i5) The partition guide's CCW angle to the rotor axis is entered as: 20 degrees.
With the above information the program determines the maximum allowed guide length as 4.04 inches.
     i6) The actual partition guide length is entered as: 4"
Next the program requires the added bearing length beyond the guide thickness.
     i7) Entered the added bearing length as (x/32): 45
The program next test the actual rotor cam grade and indicates the +/-  guide bearing arc angle minium requirement and requires an entry of the actual bearing angle selected.
     i8) Enter the +/- bearing arc angle as: 19.4 degrees.
The bearing width is next required by the program.
     i9) Enter for the bearing width: 1.5".
The program next displays information relative the bearing operation and lubrication. 
Classical lubricants only, are used for emulation of the hydrodynamic bearing operation. 
New surface treatments and synthetic lubricants/additives should permit a significant increase in the engine's  maximum operating RPM. 
The operating RPM displayed on this screen are very rough approximations, as will be demonstrated later in the program.
Enhansed cooling and lower partition inertia are made possible in the program by removing the center third of a partition's strut in very large engines; i.e. the strut is supplied with a cooling vent. 
The program asks if this vent is wanted.
     i10) Enter for partition vent: "N"
The program next permits the entry of a unique partition enertial moment.
     i11) Skip this inertia entry branch by pressing: ENTER.
The program completes the screen by displaying the partition's moment of inertia along with other relative design constants.
SCREEN 10
This screen displays the current guide bearing width and requires the entry of the value to be used.
     i1) Enter the displayed current value for the desired value of the bearing width: 1.5"
SCREEN  10+
This screen appears in the freeware downloaded prior to 02-17-00.   This is a program section is often wonky.  It  is over ambitious in its purpose for the 16 bit compiler and usually requires program code tweeking  on a design by design bases to function properly.
Generally when you see "To avoid this section enter `1' " , do so if at all possible.
     i1) To avoid this section enter '1'.   Enter :1.
SCREEN 11
This screen includes an adequate explanation of its purpose.
     i1) Enter for the number of iterations per VVC arc: 3000.
     i2) Do not select a different count press: ENTER
SCREEN 12
This screen requires an input of `1' to branch of into the spring loaded -rotor cam bearing combination partition displacing design.  If `1' is not entered the program branches to the desmodratic means.   However, at the end of the data acquisition in either branch data can then be generated in the other branch.
     i1) The spring loaded bearing combination is selected, enter: 1.
SCREEN 13
Spring loading being selected, the spring characteristics must be determined.  The program does this with the  partition inertial characteristics already determined, and the minimum spring length and maximum engine RPM inputs in this screen.  At RPMs beyond this maximum value  the partition/spring will "float".
     i1) Enter the minimum spring length: 3".
     i2) Enter for the maximum engine RPM: 6600
SCREEN 14
This screen first displays the acquired spring characteristics. 
Although the bearing cam losses are not that significant, this is probably the most important part of the program. 
At the highest possible engine RPM the hydrodynamic bearing must function. 
When the lubricant lamina thickness (qth) drops below about 1/10000 "- the program locks up and the program section must be repeated for a new bearing design which will meet the demands of the maximum engine RPM.  Increasing the bearing width and length is the quickest fix for this problem; however, cam grade, minimum cam radius, and partition guide angle are also among the other determinate characteristics. 
This program section takes a bit of time.
 i1) Enter the test rpm: 6000
The program next proceeds to access the hydrodynamic bearings characteristics at the 30000 increments in the complete traverse of the annular cavity by the partition.
SCREEN  15-
This screen permits branching to the desmodratic bearing hydrodynamic bearings emulation.
SCREEN 15
As in screen 14, this screen displays the emulation of the hydrodynamic bearings only for the desmodratic arrangement.  Although this particular arrangement requires the entry of a clearance ["slop"]  factor between the partition guide's bearings and the opposed cams of the rotor cam channel or rail, this requirement is removed when two guide partitions are used.   Each of the two guides with its hydrodynamic bearing to cam interaction coacts with the other to effect the partition's pivotal movement.
     i1) Enter the test rpm: 6000
     i2) Enter the slop (clearance) between the guide bearings and cam channel: .010"
The starting fluid lamina thickness at the bearing supporting the partition's  inertial load is required next.
     i3) Starting fluid lamina QTH: .0001"
The program then proceeds to demonstrate the desmodratic hydrodynamic bearing emulation through the 30000 increments of a partitions' annular cavity traverse.
PROGRAM SECTION  3FRASCA.exe
The program itself contains the required annotation.   Keep in mind the Sweigert-Beardsley equations for Cp variation with temperature date back to the 1938.   Newer and  more accurate empirical formulae are now available.   The annotation screens are skipped here and we pick up with:
SCREEN 16
On this screen wether or not the use of the Z factor is selected.
SCREEN 17
This program section generates and displays, in addition to the particular data needed by the program, a great deal of additional information about the initial intake air.
The program first asks if a different ambient temperature is desired for the engine performance data generation, then asks for the relative humidity of the intake air.
     i1) To enter a different ambient temperature; otherwise press: ENTER 
     i2) Enter the relative humidity: 57%
With this information the program determines and displays information including the intake air content and thermodynamic properties, and the intake air mass.
The program next requires the size of the gap at the partition edge at the rotor wave surface.
     i3) Gap (x.001") enter: 2
Next the engine operating RPM for the power generation emulation run is entered:
     i4) Test RPM: 6000
Next the screen displays the particular number of increment per VVC that are usable in the compression-
combustion emulation for the current engine design.  In the current instant the selections are: 24, 48, 72, 96 and 120.
     i5) Enter number of tests per chamber: 120
The circumferential bleed-by gaps (pgap) are entered next.  Assuming some type of dynamic flow limiting arrangement  multiples of 0.0001" are selected.
     i6) Enter (x .0001"): 2
As with the circumferential bleed-by gaps the partition framing slot gap (Fgap) is also entered in multiples of 0.0001".
     i7) The partition framing bleed-by gap is entered as  .0001 x enter: 2
SCREEN 18
THE ENGINE COMPRESSION REGION PERFORMANCE.
The top portion of the screen display some of the dimensional aspects of the gaps in the engine.
Fixed VVC mass compression.
In its center portion, the screen displays the engine's theoretical compression region performance under adiabatic conditions with constant VVC mass.  Displayed are the VVC pressure and temperature exiting the compression region, and the mean torque required for the compression region.
Displayed also are the rate of work expended in the topic compression process estimated using integration and torque approximation methods.   The estimation by torque method with greater numbers of iterations should approach closely the estimation by integration.
Compression with VVC mass loss.
The bottom portion of the screen displays the engine compression region's performance with VVC mass loss.  Note particularly the mass loss displayed as remaining mass percentage, the low energy expenditure and the effective compression ratio.  The ratio A(43) is the maximum VVC volume divided by the minimum VVC volume while the "effective compression ratio" is the actual ratio of the pressure of the VVC exiting the engine compression region to its pressure while entering the engine compression region.
NOTE: Data loading at the program end takes some time.  Do not terminate program before data load is complete.
PROGRAM SECTION:  8FRASCA.exe\3FRASCA.exe
GRAPHIC DISPLAY OF ENGINE COMPRESSION REGION  DATA.
PROGRAM SECTION 8FRASCA.exe is now run to graphically demonstrate the data collected by program section 3FRASCA.  Screens 19 & 20 display graphically the VVC temperature and  pressure data respectfully.
The filled graph is performance with mass loss.
GRAPHIC DISPLAY OF GENERATED DATA.
SCREEN 19
SCREEN 20
PROGRAM SECTION:  4FRASCA.EXE
In program section 4FRASCA, the engine's fuel is selected from a menu of 20 fuels and the air-fuel ratio is entered as a percentage.  Air-fuel ratio example: 120% air is 120% of the air required for the theoretical complete combustion of the selected  fuel. 
Using this information the VVC thermodynamic characteristics (insulated  with no mass loss processes) are assessed increment by increment in their traverse of the combustion region and the program determines the effective energy (Btu) per pound mass air for the fuel in the particular engine design.  Further explanation of this process is within the program itself.
SCREEN 21a
Here the Z factor selection made in program 3FRASCA may be deselected.
 i1) Do note deselect the Z factor use.  Press ENTER.
After this selection the program takes a few moments to generate seed date using a pseudo fuel and 100% air.
SCREEN 21b
On this screen are selected the percentage air and the type of fuel engine fuel.  The fuel type and percentage air selected will be displayed after the first complete data generation cycle.
     i1) Enter the percentage air: 120
     i2) Enter the fuel used: 5.) C13H28 (Medium diesel).
SCREEN 21c
This screen permit the entry of a unique energy value for the fuel and % air sele i1) Enter Energy quantity: Press ENTER.
SCREEN 22 
On this screen are displayed a fairly complete energy use profile for the engine combustion processes in VVC without mass loss.
PROGRAM SECTION:  8FRASCA.exe\4FRASCA.exe
GRAPHIC DISPLAY OF ENGINE COMPRESSION +  COMBUSTION REGIONS  DATA.
SCREEN 23
The filled portion of the VVC temperature graph (compressor region) is data with VVC mass loss.  The unfilled graph (compressor & combustion region) is data without VVC mass loss and heat transfer.   The region in which fuel injection occurs is indicated by the 4 parallel horizontal line segments.
SCREEN 24
The filed portion of the VVC pressure  graph (compressor region) is data with VVC mass loss.  The unfilled graph (compressor & combustion region) is data without VVC mass loss and heat transfer.   The region in which fuel injection occurs is indicated by the thick horizontal line bracket.
PROGRAM SECTION:  5FRASCA.EXE
This program generates the first approximation of engine performance.  Heat transfer is not accounted.   The programs internal annotation is adequate.
SCREEN 25a
As in the previous program sections, the Z-factor use mode may be deselected.
      i1) To keep the present Z-factor use selection press: ENTER
SCREEN 25b
A step by step view of the data collection for the combustion region traverse of the combustion region by a VVC  with perimeter bleed-by may is  availableted. 
       i1) To step through the data acquisition enter 1: 1
SCREEN 25c
This is typical of the many displays when a step by step acquisition of the VVC traverse of the combustion region with perimeter bleed-by is chosen is screen 25b.   The data is self explaining.
SCREEN 25d
This is the engine performance with perimeter bleed-by.  The data is self explaining
SCREEN 25e
PROGRAM SECTION:  8FRASCA.exe\5FRASCA.exe
GRAPHIC DISPLAY OF ENGINE COMPRESSION +  COMBUSTION REGIONS  DATA  WITH PERIMETER BLEED-BY.
SCREEN 26:
Displays  the VVC temperature data with perimeter bleed-by during their traverse of the engine's compression and combustion regions.
SCREEN 27:
Displays  the VVC pressure data with perimeter bleed-by during their traverse of the engine's compression and combustion regions.
SCREEN 28a
The program next generates the VVC data for traverse of the compression and combustion regions with mass exchange between neighboring VVC.   This screen permits  of a step by step view of this data generation.
SCREEN 28b
This is a the typical step by step display screen for the data acquisition with mass flow between neighboring VVC.  The data is self explaining.
SCREEN 28c
Displayed is the first approximation of engine performance with perimeter bleed-by and inter VVC mass exchange.
PROGRAM SECTION:  8FRASCA.exe\5FRASCA.exe
GRAPHIC DISPLAY OF ENGINE COMPRESSION +  COMBUSTION REGIONS  DATA  WITH PERIMETER BLEED-BY  AND  INTER  VVC  MASS FLOW.
SCREEN 29
Graph of the VVC temperature with perimeter and inter VVC mass flow during their traverse of the engine cavity.
SCREEN 30
Graph of the VVC pressure with perimeter and inter VVC mass flow during their traverse of the engine cavity.
PROGRAM SECTION 6FRASCA.EXE
Program section 6Frasca, generates a large quantity of nut and bolts information, including the main bearing loads, annular cavity circumference lengths which are critical for flow limiter designs and annular cavity centroid information which is critical to engine rotor balancing.   To determine the main bearing loads with a good safety margin you'll want to generate  special engine data using 3FRASCA, 4FRASCA, and 5FRASCA with the gaps, Fgaps and Pgaps zeroed in program 3FRASCA.   Save the current engine data in a separate folder for later retrieval, then start 3FRASCA again.  program 6FRASCA data is self explaining.
In single undulation and 4 cycle engines, ganging ( i.e. sharing the same power shaft) two rotors will cancel all bearing loading moments and power shaft  directed forces ( Z-axis forces) leaving only a force perpendicular to and rotating with the rotor shaft when:
the rotors'  power cycles are in phase, 
the rotors'  wave surfaces are directed towards the opposite ends of the power shaft,
the  X-Z  and Y-Z planes of the 2  rotor coordinate  systems are coincident, and
the positive X and Y axii  of the 2 rotor coordinate systems  point in the same direction.
SCREEN 31

SCREEN 32
Screens 32, 33 display the generated data for main bearing load.  Though not shown, the option to view the data generated increment by increment may be selected.
SCREEN 33
SCREEN  34
Screen 34 display results from selecting "2" in the menu and displays the dystal and proximal annular cavity circumferential lengths.   Also selectable from this screen are the display of the proximal and distal circumferential lengths between any two entered annular cavity angles and the proximal and distal circumferential lengths of a single VVC located at an entered angle between 0 and A(39) angles.  In this instance  between 0 and 88.5 degrees.
SCREEN 35a
Screen 35a, 35, 36, and 37 display the annular cavity centroid information.  In Screen 35a the exact formula in the manual used for iteration is selected. 
SCREEN 35
SCREEN 36
SCREEN 37
 TO THE FRONT PAGE
 TO THE PROGRAMS MENU