Generalized Criteria Development of The Peformance Parameter of Systems Effectiveness

ABDUL AZIZ

of

The P4-m

Para-

THE AUTHOR is a mechanical engineer with the engineering Services Division of the Naval Research Laboratory, Washington, D. C. Prior to this he was

with the Naval Ship Research and Development Center, Annupolis Division, where he worked in the MESA (Machinery Effectiveness Systems Analysis) Program sponsored by the Navy Ship Systems Command. The present paper based on his works in the MESA Program is second in number in the general area of Systems Effectiveness. H i s first paper in the same general area entitled “Systems Effectiveness in the United States Navy” was published in the December 1967 issue with subsequent discussion in the April 1968 issue of this JOURNAL. He is a member of the ASME.

Editors Note: “.The performance of a n automobile is its acceleration ability and gasoline consumption rate. The performance of a Weapon System is its target kills per square mile. But can we a m e r to the question ‘What is Performance?’ without referring to a specific equipment or a system? This is the subject mutter of this paper. The author derives generalized performance criteria and discusses their signijkance OT usefulness.”

T H E CONCEPT OF systems effectiveness is new, but the concept of performance is not. The term performance has been used in engineering ever since the. term engineering was used.Therefore, it seems, there should not be any need for a new and fresh development and discussion on the parameter performance. Yet it is true the systems effectiveness analysts are trying to define and develop the concept of performance. One should not deny the need, rather should try to understand why the need is there. I believe some of the reasons for a new and fresh discussion on the concept of performance a r e (1)At the advent of systems effectiveness there

appeared some ‘grey area’ between effectiveness and performance. Prior to the advent of systems effectiveness, no other term was used that described the similar concept either entirely or partially contained in performance. So a new look at perfonnance is needed for broadening its understanding and to differentiate it from effectiveness. (II) Before the advent of systems effectiveness, performance was an engineering term, now it is h a term. Before the advent of systems effectiveness performance was used in engineering by engineers and systems analysts with the true meaning of the word being understood purely by them. The managers had a kind of intuitive feelNaval Enqlnmn Journal, kbruary I969

47

SYSTEMS EFFECTIVENESS PERFOFWANCE CRITERIA ing of performance in that they knew ‘a better performance meant one system or an equipment performed better than the other.’ But at the advent of systems effectiveness the managers themselves became involved in systems analysis, and the kind of intuitive feeling they held previously was no longer adequate to them. Thus there is a need for a new and fresh discussion on performance. By the same reason the approach to the discussion on performance should be new and M e r e n t from that used for purely scientific and engineering presentation. The concept of performance will be developed with the help of an example. For example, let us take the feed water pump of a boiler. Further, let us propose that we want to show the following important operating relationshps concerning the Pump: 1. Head vs. Capacity, 2. Efficiency vs. Capacity, 3. Brake horsepower vs. Capacity. These operating relationships are drawn from experimental or analytical results and shown in Figures la, lb, and lc, respectively. We call and label them as: 1. Head capacity curve, 2. Efficiency curve, 3. BHP curve. Do we have to draw them in separate figures? The answer is “No.” Suppose we draw them in one figure as shown in Figure Id, what single title do we give to them? After all, do we have to give them a single title? Or is it enough that we just label the curves individually? The answer is “we do not have to, but perhaps it is better to give them a single title.” Next should we give a title just for the purpose of identifying? Or should we take time to look for a title which associates some significance to these relationships and thereby serves m e meaningful Purpose? The answer is “If possible we should give a meaningful title.” To do so we keenly observe that these pump operating relationships namely, Head capacity, Efficiency and BHP can be of significant value in the selection of a pump for a given application. These relationships are generally considered by an engineer when selecting a pump. He then expresses his selection by stating ‘the pump selected will be found to perform better in the given application.’ (Of course, this does not constitute the final selection.) The word, perform, gives us a clue as to how we find a meaningful title. We say and agree that we shall call them (Head capacity, E%iciency, BHP) by one name “Performance.” Thus, performance is a matter of name and nomenclature and of concerted opinion. The term performance has been introduced 48

Naval Engineers Journal, February 1969

AZIZ

1200 I-

1000

W W LL

z

800

0

a W

I

0

100

200

300

400

600

700

600

700

500

GPM

Figure la: Head vs. capacity.

0

100.

200

400

300

500

GPM

Figure Ib: Efeciency vs. capacity.

e m

0

100

300 400 GPM

200

600

500

Figure lc: Brake Horsepower vs. capacity.

1200

1000

* W

800

z 0

300

a W

200

0

I00

200

300

400

500

GPM

Figure Id

600

100

700

;

700

SYS'IXMS EFFECTNENESS PERFORMANCE CRITERIA

AZIZ

ihrough an arbitrary example of a boiler feed water pump. The pump operating relationships that were enveloped by the term performance may not be the same for all systems or equipments. Let us, them fore, consider many other systems and equipments to determine what have been termed performance in each case,and to arrive at generalized relationships for performance independent of systems or equipment. A thorough search into text books, literatures, and manufacturer's catalogues on the subject of performance of internal combustion engines, steam engines and turbines, power plants, ships, heat exchangers, pumps, and many other systems and equipments was made. A fraction of the search findings is reproduced in this report as a sample. This sample representation is intended to acquaint

the reader with the kind of operating relationships enveloped by the term performance in each specific case of system or equipment, and is exhibited in Figures 2a through 5.

1200 80

Load. fhouwnds a( Klbwst!,

lo00 F

l

i

2c [t]. Performance curve for steam turbo-

generator.

5

"Oy I

I

V

$40

.-

1

E . -0< .!20

f w

a

L

m

200

r

-

-New

3 x 0

7-

0

100

200

400 G P ~

300

500

600

:

,

.

Old Head Design Head

100 700

Figure 2a [l]. Performance curves for a four-stage boiler feed pump rated 450 gpm, 1,000 feet head, 71% &ciency, and 3,550 rpm.

v)

400

300 200

m

+

t y

6

g

c

THOUSAND RPM Figure 2b [2]. 4RC6 Engine Performance.

Figure 2d [&I. Performance curves of the Navy standard DB engine with old and new design cylinder heads. Naval Engineers Journal, k b r u a v I96T

49

SYSTEMS EFFECTIVENESS PERFORMANCE CRITERIA

AZIZ I

I

I

R PM Figure 2e [5]. 1-40 performance data-exhaust temperature.

Figure 2g [7]. 1-40 performance data thrust.

Figure Zf [6]. Performance of Buda 6-cylinder diesels. Automotive Models

Cylinders .................. . 6

Bore ........................ Stroke ...................... Dispkement

4

6LD-415

in.

5% in.

...............415 cu. in.

6LD-468 6 4% in. 5% in. 468 cu. in.

Maxhrua speed continuous load, ZOO0 r.p.m. Maximum speal intermittent load, 2200 r.p.m. Fuel, Diesel oil.

Each specific relationship is a measure of one aspect of performance of the system or of the equipment, and may be called a criterion. For the purpose of discussion the phrase ‘performance envelope’ will be used to denote all the performance criteria. While seeking acquaintance with the sample representation as mentioned above it is to be kept in mind that a generalization of performance criteria is being sought through observations and inferences. Figures 2a through 21 are specifically labelled 50

Naval Enqinwn Journal, February I 9 0

Figure Zh

[&I. Warm air

furnace performance in building.

performance curves by the authors of references from which they have been quoted. It was mentioned earlier that the curves which describe the operational relationships of a system or equipment need not be labelled by the single term perfomance. Figures 3a through 3h are such figures. They

SYSTEMS EFFECTIVENESS PERFORMANCE CRlTERIA

AZIZ

T e n p i d e n of Entering Alr

Figure 2i [Sb]. Performance of pin nsdietors.

I

lo0

I

J

200 250 ktk)hTharcandcof Poundto( 9ermPwHan 150

Figrve 21 [ll]. Performance of a two-drum broiler with superheater and regenerative air pheater. for: d,~[sp,or bitrrminouS 4; 926 pdg working psesun; 1,025 I& d d g n pressure; dust collector when d - & b d ; forced-and indueed-drn€t tans; dry bottoms; watenvdh; 8OF air entering prehsatu; 245 F fed-water temperature.

S Engine, r pm

O

U

I

S

800 I600 2400 3200 rod0 Engine. r pm

Figure 2 j [S]. Performanes characteristics of oldsmobile eight cylinder Rock& (3% x3-?/16) and Lint-8 (3%x 3%) engines. compression ratios 1231 and U:1, respectively.

I -

I

I Kr-7

I

*LTIMcHoRscPtmu4~

Figure 2k [lo]. Comparative performance curves d petrol and C.I. engine eirCraft (see table on p.-)

have been reproduced from materid the text of which is about performance, and have been referred to as perfomance. Performance m a y also be

sl-mvn in tabular forms or bistographical farms as SFmvn in F'igures 4a, 4b and 5, respectively. Now let us list in Table I, without ordering, the tc-ms that we have observed to be in the perfomNaval Enqlneon Jawl, hbruary IW

51

SYSTEMS EFFECTIVENESS PERFORMANCE CRITERIA EXMAW1 H E S S W E -

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1 IN. Ho. ADS.

Main Plosurc.wI Ib/sq In 8bs

Figure 3d [13b] Theoretical steam rates for condensing turbines (see also Fig. 32). (NOTE: At sea level the main pressure, expressed in pounds per square inch ABSOLUTE, is obtained by adding 14.7 to the gage pressure. The exhaust pressure, expressed in inches of mercury ABSOLUTE, is obtained by subtracting the vacuum reading from 30.)

N I B I N ( CAPABW-MW

Figure 3b [12]

0

25

50

75

100

Figrve 3e [l4]

-

C Output ot ThrOttl@FIw

Figure 3c [13a]. Charts of throttle flow versus condition of exhaust steam.

52

N a v a l Enqinoers Journal, February 1969

Outlet Temperature from BufIalo Heater Seetiom of Four C o i l s s t e a m at 5 lb Gage and Velocity of Air Computed for 70°F Air through Tabular Air Passage Area. (Drawn from Data of Buffalo Forge Co.)

AZIZ

SYSTEMS EFFECTIVENESS PERFORMANCE CRITERIA

SUMMARY OF RESULTS ANALYSIS No. .E.:.$ ........

PLANT PERFORMANCE FULL POWER OPERATION

SPEED Figure 3f [4c] Propulsive Coefecient EHP/SHP Versus RPM at speed of 16 knots.

SUP

-

Knot

-

HP

I

Plant Fuel Conaump ti on (2 Boilers)

-

S p e c i f i c Fuel Rate

-

Endurance Range

-

lb/h 1b/S H P-h hrs

mile

P l a n t Thermal Effl c l e n c y

-

4&

-

9

Ship-Propulsion Ef f l c l e n c y

CRUISING POWER OPERATION

VelocltyJn Ft per Mln.

Figure 3g [&I Heat transmitted per lineal foot of one-inch pipe of Buffalo heater sections of four c o i k t e a m at 5 Ib gage and velocity of air computed for 70” F. Air through tabular air passage area. (Drawnfrom data of Bufialo Forge Co.).

Speed

SHP

-

-

HP

-

S p e c i f i c Fuel

Rate

300

lb/SHP-hl

milea

C r u i s i n g Range

p 200

x”

z 100

Figure 4a CIS1

2

0

100

2

m 50

0 0 1 2 3 4 4 6 7 8 9 101112131415161719 I00 U S Gallons per Minute

--I

Figure 3h [15]. Curves for a pump having &inch suction and 5-inch discharge and operating at 1,750 rpm.

ance envelopes exhibited in the Figures 2a through 8. Next we classify these listed performance terms. We base our classification on the following four enqviries. 1. What is the output we want? 2. What is the economy of the desired output? 3. Is the operation giving output trouble free? 4. Is the structure supporting operation failure free?

IS62

1963

5 [18J Psrforman~-R€ air caoltng feasibility Program.

SYSTEMS EFFECTIVENESS PERFORMANCE CRITERIA

AZIZ

This classification leads to the DERnrATION OF

GENERALIZED PERFORMANCE CRlTERIA

Table f Terms in Performance Envelope

is

shown in Figure 6. So the generalized performance criteria are:1. Performance output (capacity) criteria, 2. Performance economy criteria, 3. Perfmmance criteria for smooth (trouble free) operation, 4. Performance criteria for sound (failure free) structure. These performance criteria have been developed through critical enquiries and observation of works of people for over seventy-five years. It may be pointed out that for some systems some performance terms may be found belonging to more than one performance criteria. And for some system some criteria may be totally absent. The performance economy criteria is of special interest to the systems analyst. Ecoaomy consideration such as capital cost, maintenance cast are not enveloped by the performance economy criteria. Performance economy criteria envelop only thw aspects of performance economy which indicate any or all of the following dependent operating relationships: 1. the &ciency with which a system input is converted into a system output, such as thermal efficiency. Thermal efficiency is a

Brake horsepower Torque Specific fuel consumptior RPM Turbine steam rate Turbine throttle flew Thermal efficiency Rankine cycle ratio Kw

B.M.E.P. Exhaust temperature BTU capacity Draft loss Combustion rate Thrust Speed Range

Altitude Air outlet temperature Steam rate of a boiler Heat rate Flue gas temperature Shaft horsepower Effective horsepower EHP/SHP Pump head NPSH GPM Exhaust pressure Exhaust enthalpy Exhaust quality Mechanical efficiency Stress Recirculation ratio

DEVELOPMENT OF GENERALIZED PERFORMANCE CRITERIA THROUGH OBSERVATION AND CRITICAL ENQUIRY

.

IhouCt p r m r

stw

SPEED RANGE

EHP TOROUE

BTU

BnP

KW

PERFORMANCE OUTPUT ICAPACITVI CRITERIA

STEAM FLOW GPM THRUST HEAD EVAPORATION RATE EMEP HEATER OUTLET TEMPERATURE

I I

GET THE DESIRED OUTPUT?

I

.-. .

4. ISTHE STRUCTURE

MECH EFFICIENCY TH EFFICIENCY EXHAUST TEMP DRAFT LOSS

HEAT RATE FLUE GAS TEMP. EXHAUST PRESSURE EHPEHP

SPECIFIC FUEL CONSUMPTION

RANKINE CYCLE RATIO

COMBUSTION RATE EXHAUST ENTHALPY

SUPERHEAT EXHAUST QUALITY

I

PERFORMANCE ECONOMY CRITERIA I

I

._______ I ____.I

SUPPORTING OPERATION FAILURE FREE?

54

.

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Naval Engineers Journal. February I 9 0

r

STRESS

PERFORMANCE CRITERIA FOR SOUND (FAILURE FREE) STRUCTURE

STRUCTURAL PERFORMANCE

SYSTEMS EFFECTIVENESS PERFORMANCE CRITERlA

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major performance economy criterion for any energy conversion system. 2. any operating condition found to index loss in the process of systems operation, such as flue gas temperature of a boiler. 3. any operating condition considered to index the rate of output, but distinct from output, such as exhaust steam condition of a turbine. 4. rate of a system input, such as specific fuel consumption of an engine. Having thus developed the generalized performance criteria we must test the strength of generalization and illustrate applications. This is done in Figure 7. This figure is an illustration and does not aim to cover all performance terms in the performance criteria for the systems illustrated. Given the performance terms, this figure illustrates that, they can be grouped in the four criteria developed. This has been done with many systezns--chosen arbitrarily. Therefore, the development of the four performance criteria is general. To test the strength of generalization two unorthodox systems have been included, i.e. an R&D laboratory, and an employee. It may be mentioned here that, though it has been possible to diagnose

and group the various performance terms in the four performance criteria for these two systems, their evaluation is not easy. In Figure 10 systems have been shown to be grouped as energy conversion; transfer; conversion and transfer; conversion, transfer and utilization; and detection, measure and control systems. In the classification of performance criteria, this systems classification has no service. Performance criteria classification is independent of systems classification. This generalization of performance criteria can be applied to enemy detection and destruction systems,i.e. the weapons system-or to any other system in existence or yet to be developed. The significance of this generalized performance criteria development is great. When the resew&, development, design and operations experts have determined the performance envelope the systems analyst can group the various performance terms in the four performance criteria. On the other hand for newly created systems as well as for unorthdox systems the systens analyst has established a language for communication with the above experts. He now can ask them what to look for as performance of systems.

Test and Application of Generalized Performance Criteria Performance Output Criteria

Systems

1

Boiler

Energy Conversion Systems

Turbine

Performance Economy Criteria

Performance Smooth Operation C r i t e r i a

Evaporative Capacity Boiler Efficiency Steam Quality Combustion Efficiency Pressure Flue Gas Temp.

Recirculation Ratio Steam Quality at Exit*

SHP RPM

Turbine Efficiency Steam Rate Exhaust Cond.

Thermodynamic Operation

CPM

Efficiency BHP

NPSH

Sttesses

1

Reduction Gear Pump

HP Torque Gear Ratio

Efficiency

Backlash

Stresses

____ Energy Conv. and Transf. Systems

3

Propulsion System

EHP Torque RPM

Specific Fuel Consumption

Smooth Operation of Sub Systems

Stresses

--

Ship

Energy Conv., Transfer and Utilization Systems

Speed Range Displacement

Specific Fuel Consumption

Sea Worthiness and Other Smooth Operation Criteria

Stresses

Air Craft

Specific Fuel Consumption

Sky Worthiness and Other Smooth Operation C r i t e r i a

Stresses

~

f

;

Galvanometer Flow Meter

1

~

~

~

~

E;zEz;tion,

Control Systems

1

Il&D Laboratory

~

Satisfactory Human Relations

Sound Organization

Adjustment, Interest Cooperation Conduct, Appearance

Physical Fitness

~Range~

g

,

e

c

.____

I

I

Sensitivity

Accuracy

R&D Report and Product**

Misc. Systems

'in Employee

I

1

Speed Range Ceiling Pay Load

-.

Stresses

I

~~

Energy Transfer Systems

Performance Sound Structure C r i t e r i a

Quantity of Work Quality of Work

Labor (Direct and Indirect) Procurement (Direct) Punctuality, Attendance Industry

Naval -In-n

Journal, kbruary 110

55

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SYSTEMS EFFECTIVENESS PERFORMANCE CRITERIA

[l] Philip J. Potter, Steam Power Plants. [Z] Max Bemtele, “Curtiss-Wright Rotating Combustior. Engine Today”. C31 J. S. Dolittle, Engineering Thermodynamics. [4] Transactions, The Society of Naval Architects and Marine -ems, Vol. 56-1948. [5] E. T. Vincent, Theory and Design of Gas Turbines and Jet Engines. [6] B. J. Von Bongart, Diesel Engines. [7] E. T.Vincent, Theory and Design of Gas Turbines and Jet Engines. [a] Arthur M. Greene, Jr., Principles of Heating and Ve2ltilatill.g. [9] L. C. Litchy, Internal Combustion Engines. [lo] Arthur W. Judge, High Speed Diesel hgines.

[ll] Philip J. Potter, Steam Power Plants. D. Wilson, “Cross Coupled Compound Arrangements for Compact Large Capability Steam Turbine Generator Units”,ASME paper no. 54-A-182. [13] Louis E. Newman, Modem Turbines. [14] Arthur M. Green, Jr., Principles of Heating and Ventilating. [15] J. A. Cable, “Selection of Centrifugal Pumps”, AllisChalmers Mfg. Co. Cat. no. 52R7904. [16] Ship Propulsion Design Analysis, 1965-66, United States Naval Academy Ehgineering Department. [17] Transactions, The Society of Naval Architects and Marine Engineers. vol. 62-1954. [18] Charles Jones, “The Curtiss-Wright Rotating Combustion Engine Today”, SAJZ Transaction vol. 73-1965.

[El Charles

THAT PAY CHECK Surveys, polls, opinion research-these have become a way of life in the U. S. There i s the Gallup Poll, the Harris Poll, Opinion Research, Neilsen, Trendex all hopefully bringing in dependable information for specific purposes: all determining facts regarding a condition or conditions; or obtaining a systematic collection and analysis of data on some particular aspect of a group of people. Which brings US to our subect, a survey close to all engineers’ hearts: Where do engineering salaries stand? they continue to rise? Are you above or below the norm? How much will companies be offering to attract the engineers they need at all degree levels? The Engineering Man wer Commission of Engineers Joint Council, a private, nonproft organization o professional engineering societies, proposes to find the answers through its biennial survey of engineers’ salaries. EMC has been performing this service since 1953 and publishes its findings in the form of detailed maturity curves of salary as a function of years since graduation. This year, EMC is offering new companies an opportunity t o participate in these surveys, thereby producing a more complete cross section. Here are some points for participating companies: I Results are available to industry in meaningful form-the more companies participate, the better the data and the more detailed the reports. 2 All participants receive complimentary reports. 3 Since EMC i s a disinterested, nonprofit organization, all semblance of collusive action is eliminated. 4 Companies are assured that their replies are handled confidentially, without risk of unwanted disclosure t o outsiders. The 1966-1967 survey incorporated replies from I145 employers of 189,407 engineers, about one third of the engineers employed in the U. S. Median salaries for nonsupervisors and supervisors (all degree levels combined) at that time were $12,550 and $15,650 respectively. Also brought out in that survey was the value of higher education. Here are the figures for all engineers, supervisory and nonsupervisory combined, analyzed by degree level: Bachelor’s degree--$I2,100; Master’s degree$13,600: Doctor’s degree-$I6,350. Figures obtained elsewhere: If you wanted t o do slightly better than the median Bachelordegree engineer, you could have been a median personnel director, chief accountant, or economist. If you had a Master’s degree, you had only the median attorney ($14,750) and medical doctor ahead of you. With a Doctorate in engineering, you were second only to the medical doctor, who probably earned his median $28,960. Sidelight: Thirteen years ago, the starting salary for new graduate engineers was $4050, and it has now grown to $8350, a steady seven percent increase in spite of booms, recessions, and wars. While the EMC salary survey is the most detailed and comprehensive of i t s kind in the U. S., t h e is mom for improvement. The Commission i s particular1 anxious to obtain more responses from industry in the mechanical engineering &Id. The 1968-1969 survey got under way in August, and we urge companies who would like to participate, or who would like further information, to write to the Executive Secretary, Engineering Manpower Commission of Engineers Joint Council, 345 East 47th Street, New York, N. Y. I0017. Greater su port and participation by industry can result in more meaningful and useful salary eta.

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N a v a l Engineers Journal, February I969