In
engineering
Engineering is the use of scientific method, scientific principles to design and build machines, structures, and other items, including bridges, tunnels, roads, vehicles, and buildings. The discipline of engineering encompasses a broad rang ...
, heuristics are experience-based methods used to reduce the need for calculations pertaining to equipment size, performance, or operating conditions. Heuristics are fallible and do not guarantee a correct solution. It is important to understand their limitations when applying them to different equipment and processes. Though heuristics are limited, they may be of value. This is because they offer time-saving approximations in preliminary process design.
Problem solving methods are intrinsic to
forensic engineering
Forensic engineering has been defined as ''"the investigation of failures - ranging from serviceability to catastrophic - which may lead to legal activity, including both civil and criminal".'' It includes the investigation of materials, product ...
methods, where failures are analysed for the
root cause Root cause may refer to:
* "Root Cause" (''Person of Interest''), a TV show episode
* Root cause analysis
In science
Science is a systematic endeavor that builds and organizes knowledge in the form of testable explanations and predic ...
or causes. Only when failures have been investigated with conclusive results can remedial action be taken with confidence.
Examples
Storage Vessels
These heuristics were taken from Turton's "Analysis, Synthesis, and Design of Chemical Processes".
*Use vertical tanks on legs when the tank is less than 3.8 m
3.
*Use horizontal tanks on concrete supports when the tank is between 3.8 and 38 m
3,
*Use vertical tanks on concrete pads when the tank is beyond 38 m
3,
*Liquids subject to breathing losses may be stored in tanks with floating or expansion roofs for conservation.
*Freeboard is 15% below 1.9 m
3 and 10% above 1.9 m
3.
*Thirty-day capacity often is specified for raw materials and products, but depends on connecting transportation equipment schedules.
Pumps
A pump is a device that moves fluids (liquids or gases), or sometimes slurries, by mechanical action, typically converted from electrical energy into hydraulic energy. Pumps can be classified into three major groups according to the method they u ...
These heuristics were taken from Turton's "Analysis, Synthesis, and Design of Chemical Processes".
[Turton, Richard, et al. (2003) ''Analysis, Synthesis, and Design of Chemical Processes'', Upper Saddle River, NJ: Prentice Hall. {{ISBN, 0-13-064792-6]
*Centrifugal pumps: Single Stage: for of 0.057-18.9 m
3/min, 152 m maximum head. Multistage: for 0.076-41.6 m
3/min, 1675 m maximum head. Efficiency is 45% at 0.378 m
3/min, 70% at 1.89 m
3/min, 80% at 37.8 m
3/min.
*Axial pumps: for 0.076–378 m
3/min, 12 m head, 65-85% efficiency.
*Rotary pumps: for 0.00378-18.9 m
3/min, 15,200 m head, 50-80% efficiency.
*Reciprocating pumps: for 0.0378-37.8 m
3/min, 300 km head maximum. Efficiency is 70% at 7.46 kW, 85% at 37.3 kW, and 90% at 373 kW.
References